Intercensal and Postcensal Estimates of April 1 County Population by Age and Sex: 1980-2009

Fall 2009

The procedure used to develop these age-gender estimates for counties is a share method. The method relates each county's age-gender distribution in 2000 census to the state's age-gender distribution in 2000. County age-gender distributions are moved forward each year by applying the county 2000 shares to age-gender population estimates developed at the state level by a cohort-component survival technique. This is a relatively simple and reasonably accurate procedure for developing a full range of age-sex population estimates for counties. When last tested, the average error was ten percent for all age groups across all counties when compared to census counts a decade later. See technical notes PDF

Please Note: These estimates may not match the population estimates developed by other methods on the OFM website or in publications.

Population Tables

  1. 1980-2009 State and County April 1 Population Estimates by Age and Sex (PDF files). These tables contain five-year cohorts, 15-17 year old age groups, and median age. The fall 2009 data update includes updates for years 2008-2009.

    2. State of Washington Ferry County Klickitat County Skamania County
    Adams County Franklin County Lewis County Snohomish County
    Asotin County Garfield County Lincoln County Spokane County
    Benton County Grant County Mason County Stevens County
    Chelan County Grays Harbor County Okanogan County Thurston County
    Clallam County Island County Pacific County Wahkiakum County
    Clark County Jefferson County Pend Oreille County Walla Walla County
    Columbia County King County Pierce County Whatcom County
    Cowlitz County Kitsap County San Juan County Whitman County
    Douglas County Kittitas County Skagit County Yakima County

  2. 1990-2009 State and County April 1 Population Estimates by Age and Sex. These tables contain five-year cohorts, and 15-19 single year of age.  The fall 2009 data update includes updates for years 2008-2009. Excel  |  Self-extracting SAS data file
  3. 1980-1989 State and County April 1 Population Estimates by Age and Sex. These tables contain five-year cohorts, 15-17 year old age groups, and median age. Excel

Last modified: August 25, 2009
E-mail: OFM.Forecasting@ofm.wa.gov