...Oct 31, 2011.
The world population has gone up by 350%, from 2 billion people to 7 billion people, in just 84 years!
The 7 billion mark is a huge spike from less than a century ago. In 1927, the global population was 2 billion.
It was only 13 years ago that the population was at 6 billion, the United Nations says.
Changing demographics are quickly reshaping the world in numerous ways.
People under the age of 25 make up 43% of the world's population, the United Nations says.
About half of the world's population lives in cities. Within about 35 years, two-thirds will, it says.
Total population is still climbing, but the rate of growth peaked in the 1960s at about 2 percent. It has steadily declined since then, although it remains well above replacement level in places like sub-Saharan Africa, where it still tops 2 percent.