- By 2050, there will be around 9.3 billion people and more than 10 billion by 2100. But this could be as high as 10.6 billion by 2050 and more than 15 billion in 2100, with only a small rise in fertility in high-population countries.
- Each year around 80 million are added to the world's population, a number roughly equivalent to the population of Germany, Vietnam or Ethiopia. People under 25 comprise 43 per cent of the world's population.
- The main reason for the demographic surge of recent decades is the Baby Boom of the 1950s and 60s, which shows up in ensuing "bulges" when this generation reproduces.
- Average life expectancy rose from about 48 years in the early 1950s to about 68 in the first decade of the new millennium. Infant mortality fell by nearly two-thirds.
- Contraception, prosperity and changing cultural attitudes have also brought about a fall in fertility, from a statistical 6.0 children per woman to 2.5 over six decades.
- In more advanced economies, the average fertility rate today is about 1.7 children per woman, below the replacement level of 2.1. In the least developed countries, the rate is 4.2 births, with sub-Saharan Africa reporting 4.8.
- Asia accounts for 4.2 billion of the world's population. It is projected to reach 5.2 billion in 2052 before declining slowly. The biggest rate of increase is in Africa, whose population first surpassed a billion in 2009 and is expected to add another billion by 2044.
- China is the world's most populous country, with 1.35 billion, followed by India with 1.24 billion. In 2025, India will have 1.46 billion, overtaking China's 1.39 billion. China's population will decline to about 1.3 billion by 2050; India's will peak at 1.7 billion by 2060.
- Under the UN Millennium Goals, access to reproductive health should be universal by 2015. But there are still 46 countries where a fifth or more of women who are married or living in a union still have an unmet need for contraception, particularly in sub-Saharan Africa. Gender equality and women's empowerment are also keys to lowering birth rates.
See how how we got to 7 billion: