In the twentieth century, the world’s population grew at an amazing rate.
In 1960, there were 3 billion people on Earth.
Just 40 years later, the number of people more than doubled, to 6.1 billion.
In the 12 years between 1987 and 1999, the earth gained 1 billion people.
Population experts predict that the population will grow by another 1 billion people, for a total of 7 billion, by around 2012.
Then growth is expected to slow down a bit, as women in many countries start to have fewer children.
By 2050, experts at the United Nations predict, there will be between 8 and 11 billion people on Earth.
About that time, it is expected that the population will begin to stabilize.