A census of the world population is taken every ten years
A census is taken in the various countries of the world roughly every ten years. In China, six million enumerators were needed in 2010 to go around every household to collect information on forms. In Finland, on the other hand, the population census at the turn of last year was hardly noticeable. Since 1990, Statistics Finland has been carrying out censuses directly based on administrative registers without troubling the citizens, but in most parts of the world, censuses still rely on the conventional method of interviews. Following a UN recommendation, an effort is made to conduct population censuses always in years ending with a ten, while in practice the time of the census may vary in different countries. The first data for the census of 2010, for example, had already been collected in 2005 in some countries, whereas in others they will not be collected until 2014. In April 2011, an estimated 79 per cent of the world population had been enumerated, and a census had been carried...