Total fertility rate (TFR), teen birthrates, and birthrates by age. In Oregon from Oregon Center for Health Statistics, Oregon Vital Statistics Annual Reports, http://www.dhs.state.or.us/dhs/ph/chs/data/annrep.shtml; and Chris Bushore, data analyst, Center for Health Statistics, Oregon Department of Human Services. In Washington from Washington Office of Financial Management, "Intercensal and Postcensal Estimates of County Population by Age and Sex: 1980-2008," www.ofm.wa.gov/pop/coagemf/; Washington Center for Health Statistics, "Birth Data Tables," www.doh.wa.gov/ehsphl/chs/chs-data/birth/bir_vd.htm; and Office of Financial Management, "Population," www.ofm.wa.gov/pop; and Washington Center for Health Statistics, "Natality Table A10: Age Specific Live Birth Rates By County of Residence, 2007," www.doh.wa.gov/ehsphl/CHS/chs-data/birth/htmltables/a10.htm. In Idaho from Idaho Department of Health and Welfare, Bureau of Health Policy and Vital Statistics, Annual Reports, www.healthandwelfare.idaho.gov; Idaho Bureau of Health Policy and Vital Statistics; Teneale A. Chapton, senior research analyst, Idaho Bureau of Health Policy and Vital Statistics; and Jamie Clark, senior research analyst, Idaho Bureau of Health Policy and Vital Statistics. In British Columbia from David O'Neill, manager population section, BC Stats; and BC Stats, "Live Births Per Thousand Women in Age Group," www.bcstats.gov.bc.ca/data/pop/vital/lha_asfr.asp.
Total fertility rate (TFR) is a "synthetic measure": it calculates how many children a hypothetical woman between the ages of 15 and 45 would give birth to, if at each year of age she had as many births as was average among Northwest women of that age during the period in question. When the average age of mothers is rising (as in the Northwest), the TFR understates how many children women are typically having; from John Bongaarts, "The End of the Fertility Transition in the Developed World," Population and Development Review, Sept. 2002. Sightline also calculated completed fertility rates -- how many children 45-year-old women have had, on average -- for the Northwest. Women in the region are having families larger by about 0.1 to 0.2 children than suggested by the total fertility rate.
Family size and changing age demographics derived from US Census Bureau, Population Estimates Archives, "Pre-1980," www.census.gov/popest/archives/1980s/80s_st_age_sex.html; US Census Bureau, Population Estimates Archives, "1990s," www.census.gov/popest/estimates.php; US Census Bureau, population estimates by state," www.census.gov/popest/states/; and BC Stats, "British Columbia Population Forecast 08/056: Table 3: Selected Age Groups," www.bcstats.gov.bc.ca/data/pop/pop/project/bctab3.asp.
Unintended and mistimed pregnancies. Idaho figures from Idaho Department of Health and Welfare, "Intendedness of Pregnancy," healthandwelfare.idaho.gov; Idaho Bureau of Health Policy and Vital Statistics, 2001 Pregnancy Risk Assessment Telephone Survey, (Boise: Idaho Department of Health and Welfare, 2003). Oregon figures from Oregon Department of Human Services, Pregnancy Risk Assessment Monitoring System (PRAMS), www.cdc.gov/PRAMS/States/Oregon.htm. Washington figures from Linda Lohdefinck, Pregnancy Risk Assessment Monitoring System, Washington Department of Health.
(Sources updated January 2009.)