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King County, WA Population by Age

The median age in King County, WA is 37.1, as per 2021 ACS 5-Year Estimates. Of the total population, 16.94% were under the age of 15, 20.16% aged 15 to 29, 49.76% aged 30 to 64, 11.44% aged 65 to 84, and 1.70% were 85 years of age and older.
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By Neilsberg Research
Updated Sep 17, 2023

King County, WA population age distribution

A complete breakdown of King County's age demographics from 0 to 85 years, distributed across 18 age groups is listed in the table below.

Age Group Population % of Total Population
Under 5 years 125,112 5.58%
5 to 9 years 126,721 5.65%
10 to 14 years 127,726 5.7%
15 to 19 years 121,021 5.4%
20 to 24 years 131,553 5.87%
25 to 29 years 199,084 8.88%
30 to 34 years 207,221 9.25%
35 to 39 years 184,337 8.23%
40 to 44 years 162,263 7.24%
45 to 49 years 152,568 6.81%
50 to 54 years 143,746 6.41%
55 to 59 years 138,014 6.16%
60 to 64 years 126,958 5.67%
65 to 69 years 101,790 4.54%
70 to 74 years 78,638 3.51%
75 to 79 years 45,320 2.02%
80 to 84 years 30,665 1.37%
85 years and over 38,139 1.7%
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TABLE OF CONTENTS

King County, WA population by age group

Key stats
632,133
Population under 25 years
752,905
Population aged 25-44
561,286
Population aged 45-64
294,552
Population aged 65+

Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The graph shows King County's population by age group, with age group on x-axis and the respective age group's percent of the total population on y-axis
King County, WA population by age group. The largest age group was 30-34 years with a poulation of 207,221 (9.25% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

The largest age group in King County, WA was for the group of age 30-34 years with a population of 207,221 (9.25%), according to the 2021 American Community Survey.

At the same time, the smallest age group in King County, WA was the 80-84 years with a population of 30,665 (1.37%).

King County, WA population by age cohort

To better understand the age distribution of King County, WA's population, we divided it into the following 3 cohorts:

  • Children : Under the age of 18 years
  • Adults (working population): Between the age of 18 and 64 years
  • Seniors: 65 years and above
The pie chart shows King County's population divided into segments, with each segment representing an age cohort. The area of each segment is in the same proportion of a circle as the population of the cohort is of the total population.
King County, WA population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). The largest age group was 18 - 64 years with a poulation of 1,493,834 (66.66% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Here's the population for each of the three cohorts.

Age Group Population % of Total Population
Under 18 years 452,490 20.19%
18 to 64 years 1,493,834 66.66%
85 years and over 294,552 13.14%
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Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:

  • King County's population under 18 was 20.19%, compared to the 22.51% nationwide.
  • King County's working population (between 18 and 64) was 66.66%, compared to 61.45% nationwide.
  • King County's elderly or the senior population (over 65 age) was 13.14% as compared to 16.04% nationwide.

King County, WA population pyramid

Population pyramid for King County, WA is charted below using the estimates from U.S. Census Bureau's American Community Survey 5-Year estimates. A wide base suggests population increase, narrow base indicates declining birth rates.

Key stats from our analysis of the King County's population pyramid:

  • Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for King County, WA, is 24.2.
  • Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for King County, WA, is 18.8.
  • Total dependency ratio for King County, WA is 43.0.
  • Potential support ratio, which is the number of youth (working age population) per elderly, for King County, WA is 5.3.
The graph shows King County's population across different age group and gender, with population on x-axis and population y-axis. The male population is plotted on the left in blue color whereas the female population is plotted on the right in pink color.
King County, WA population pyramid i.e. King County population distrubution across age and gender. Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Here's the King County, WA's male and female population across different age groups:

Age Group Population(Male) Population(Female) Total Population
Under 5 years 64,141 60,971 125,112
5 to 9 years 64,667 62,054 126,721
10 to 14 years 65,132 62,594 127,726
15 to 19 years 61,145 59,876 121,021
20 to 24 years 67,113 64,440 131,553
25 to 29 years 103,691 95,393 199,084
30 to 34 years 108,502 98,719 207,221
35 to 39 years 96,597 87,740 184,337
40 to 44 years 83,129 79,134 162,263
45 to 49 years 78,357 74,211 152,568
50 to 54 years 73,786 69,960 143,746
55 to 59 years 69,334 68,680 138,014
60 to 64 years 64,058 62,900 126,958
65 to 69 years 49,526 52,264 101,790
70 to 74 years 35,785 42,853 78,638
75 to 79 years 20,341 24,979 45,320
80 to 84 years 12,978 17,687 30,665
85 years and over 13,942 24,197 38,139
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Things to know

What is the population of King County, WA under 18?

King County's population under the age of 18 is 452,490, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 20.19% of the total resident population of King County, WA.

What is the aging population in King County, WA?

King County's population aged 65 years and above was 294,552. As per the U.S. Census Bureau's American Community Survey, this population is 13.14% of the entire population.

References

Datasets

King County, WA Age Group Population Dataset: A complete breakdown of King County age demographics from 0 to 85 years, distributed across 18 age groups
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the King County population distribution across 18 age groups. It lists the population in each age group along with the percentage population relative of the total population for King County. The dataset can be utilized to understand the population distribution of King County by age. For example, using this dataset, we can identify the largest age group in King County.

Key observations

The largest age group in King County, WA was for the group of age 30-34 years with a population of 207,221 (9.25%), according to the 2021 American Community Survey. At the same time, the smallest age group in King County, WA was the 80-84 years with a population of 30,665 (1.37%). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

King County population by age group

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age groups:

  • Under 5 years
  • 5 to 9 years
  • 10 to 14 years
  • 15 to 19 years
  • 20 to 24 years
  • 25 to 29 years
  • 30 to 34 years
  • 35 to 39 years
  • 40 to 44 years
  • 45 to 49 years
  • 50 to 54 years
  • 55 to 59 years
  • 60 to 64 years
  • 65 to 69 years
  • 70 to 74 years
  • 75 to 79 years
  • 80 to 84 years
  • 85 years and over

Variables / Data Columns

  • Age Group: This column displays the age group in consideration
  • Population: The population for the specific age group in the King County is shown in this column.
  • % of Total Population: This column displays the population of each age group as a proportion of King County total population. Please note that the sum of all percentages may not equal one due to rounding of values.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for King County Population by Age. You can refer the same here

King County, WA Age Cohorts Dataset: Children, Working Adults, and Seniors in King County - Population and Percentage Analysis
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the King County population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). It lists the population in each age cohort group along with its percentage relative to the total population of King County. The dataset can be utilized to understand the population distribution across children, working population and senior population for dependency ratio, housing requirements, ageing, migration patterns etc.

Key observations

The largest age group was $b3_v1 with a poulation of $b3_v2 ($b3_v3 of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

King County population by age cohort

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age cohorts:

  • Under 18 years
  • 18 to 64 years
  • 65 years and over

Variables / Data Columns

  • Age Group: This column displays the age cohort for the King County population analysis. Total expected values are 3 groups ( Children, Working Population and Senior Population).
  • Population: The population for the age cohort in King County is shown in the following column.
  • Percent of Total Population: The population as a percent of total population of the King County is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for King County Population by Age. You can refer the same here

King County, WA Population Pyramid Dataset: Age Groups, Male and Female Population, and Total Population for Demographics Analysis
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the data for the King County, WA population pyramid, which represents the King County population distribution across age and gender, using estimates from the U.S. Census Bureau American Community Survey 5-Year estimates. It lists the male and female population for each age group, along with the total population for those age groups. Higher numbers at the bottom of the table suggest population growth, whereas higher numbers at the top indicate declining birth rates. Furthermore, the dataset can be utilized to understand the youth dependency ratio, old-age dependency ratio, total dependency ratio, and potential support ratio.

Key observations

  • Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for King County, WA, is 24.2.
  • Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for King County, WA, is 18.8.
  • Total dependency ratio for King County, WA is 43.0.
  • Potential support ratio, which is the number of youth (working age population) per elderly, for King County, WA is 5.3.

King County population pyramid

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age groups:

  • Under 5 years
  • 5 to 9 years
  • 10 to 14 years
  • 15 to 19 years
  • 20 to 24 years
  • 25 to 29 years
  • 30 to 34 years
  • 35 to 39 years
  • 40 to 44 years
  • 45 to 49 years
  • 50 to 54 years
  • 55 to 59 years
  • 60 to 64 years
  • 65 to 69 years
  • 70 to 74 years
  • 75 to 79 years
  • 80 to 84 years
  • 85 years and over

Variables / Data Columns

  • Age Group: This column displays the age group for the King County population analysis. Total expected values are 18 and are define above in the age groups section.
  • Population (Male): The male population in the King County for the selected age group is shown in the following column.
  • Population (Female): The female population in the King County for the selected age group is shown in the following column.
  • Total Population: The total population of the King County for the selected age group is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for King County Population by Age. You can refer the same here

Explore related topics

King County, WA Demographics King County, WA Population

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Neilsberg Research
Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.
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Collection 5 Resources