"Population" or "inhabitants" means with reference to any county, city, town, political subdivision of the Commonwealth or any combination thereof, the natural persons in such county, city, town, political subdivision or combination as shown by the unadjusted United States decennial census last preceding the time at which any provision dependent upon population is being applied or the time as of which it is being construed. Where two or more political subdivisions are consolidated, the population of the consolidated county or city or other political subdivision shall be the combined population of the consolidating subdivisions, under the last preceding unadjusted United States decennial census.
Va. Code § 1-235