Population 2020
It took more than 50,000 years for world population to reach 1 billion people. Since 1960, we have added successive billions every one to two decades. The world population was 3 billion in 1960; it reached 6 billion around 2000, and the United Nations projects it will surpass 9 billion by 2037. The population growth rate has been slowing, however, from peak annual rates in excess of 2 percent in the late 1960s, to about 1 percent currently, to half that by 2050.