How well do we know the present size and trend of the world's population?

For the middle of 1959, the number of human beings in the world was estimated as 2,907 million, an increase of 412 million over the estimate for mid-year 1950. If these figures were exact, they would mean that world population increased, from 1950 to 1959, at an average annual rate of 1.72 per cent; and in absolute numbers, the annual arithmetic average addition to world population would now stand at about 46 million. Are the estimates accurate enough to support such inferences? What is the range of possible error in the estimated world totals and the figures for world regions?

Related Subject(s): Population and Demography