The Economist has an interesting article on the politics of census taking.
Counting can be even more dangerous than being counted. In 1936 Stalin told his officials that the following year's census would find a total population of 170m—a figure that took no account of his slaughter of millions in famines and purges. But the enumerators found only 162m people, and also revealed other unwelcome facts, including that nearly half the population of this avowedly atheist country was religious. So Stalin denounced the count as a “wrecker's census” and had the census takers either imprisoned or shot. A new count in 1939 came up with a similar total, but this time officials wisely classified the results and gave Stalin his figure of 170m.Thomas Jefferson, on the other hand, was "so fond of enumeration that he once wrote to a friend that he had 'ten and one-half grandchildren, and two and three-fourths great-grandchildren', and that 'these fractions will ere long become units.'"