Other pages about the topic: April 1
OFM 2011 through 2020 estimates are based on 2010 census data. Results from the 2020 Census are not available yet. OFM Small Area Demographic Estimates from 2011 forward will be revised after detailed 2020 Census data are released.
Intercensal estimates are estimates that are bracketed on both sides by decennial census or state-certified special census counts. As such, they yield a more consistent series than postcensal estimates which only reference the prior census point.
RCW 43.62.030 states that the Office of Financial Management (OFM) shall annually determine the April 1 populations of all cities and towns of the state. OFM population estimates for cities and towns are used in state program administration and in the allocation of selected state revenues (RCW 43.62.020). Population estimates for counties are used to allocate revenues as specified in RCW 36.13.100 and RCW 43.62.030.