The office of financial management shall determine the population of each county of the state annually as of April 1st of each year and on or before July 1st of each year shall file a certificate with the secretary of state showing its determination of the population for each county. The office of financial management also shall determine the percentage increase in population for each county over the preceding ten-year period, as of April 1st, and shall file a certificate with the secretary of state by July 1st showing its determination. At least once every five years or upon the availability of decennial census data, whichever is later, the office of financial management shall prepare twenty-year growth management planning population projections required by RCW 36.70A.110
for each county that adopts a comprehensive plan under RCW 36.70A.040
and shall review these projections with such counties and the cities in those counties before final adoption. The county and its cities may provide to the office such information as they deem relevant to the office's projection, and the office shall consider and comment on such information before adoption. Each projection shall be expressed as a reasonable range developed within the standard state high and low projection. The middle range shall represent the office's estimate of the most likely population projection for the county. If any city or county believes that a projection will not accurately reflect actual population growth in a county, it may petition the office to revise the projection accordingly. The office shall complete the first set of ranges for every county by December 31, 1995.
A comprehensive plan adopted or amended before December 31, 1995, shall not be considered to be in noncompliance with the twenty-year growth management planning population projection if the projection used in the comprehensive plan is in compliance with the range later adopted under this section.