On a global scale, the current (2010) round of the population and housing census is being conducted in 228 countries around the world.  Thailand has successfully completed ten rounds of its own Census, with the first round being conducted in 1910.  The 2010 Census represents the eleventh round and marks the 100 year anniversary of the first Thai census.  The National Statistical Office (NSO) has designated September 1, 2010 as the “National Census Day.”  Thus, even though the Census data collection takes place over many weeks, the reference time period for all data documented in the 2010 Census are assigned to September 1.   In this way, the data provide an unambiguous, precise, complete, and quality measurement of the population.

Population and Housing
Census Fact sheet