I'm Gwen Outen with the VOA Special English Development Report.

A United Nations report says the number of people in the world is expected to reach 6500 million this July. By the middle of the century, the population could reach more than 9000 million. That would be an increase of 40 percent. These numbers are fresh estimates for a report on world population change from 1950 to 2050.

Hania Zlotnik is director of the UN Population Division. She says the world has added near 500 million people in the last six years. But in her words, the good news is that new estimate show that it would take a little longer to add the next 500 million. Ms. Zlotnik says this will probably happen by 2013.

The UN report says most population growth by 2050 will take place in less-developed countries. Their population is expected to increase from 5000 million today to almost 8000 million. The population of more developed nations is expected to stay about the same as just over 1000 million.

The report says nine countries will be responsible for about half the world population increase by 25. These include Bangladesh, China, the Democratic Republic of Congo, Ethiopia, and India. The others are Nigeria, Pakistan,Uganda and the United States.12 countries are expected to have populations at least three times the size now. These include Afghanistan, Burkina Faso, Burundi, Chad, Congo and the Democratic Republic of Congo and East Timor. The others are Guinea-Bissau, Liberia, Mali, Niger and Uganda.

This report says birth rates remain low in 44 developed countries. Today, world wide there is an average of 2.6 children per woman. This number is expected to fall to just over two children per woman in 2050. But UN population experts note that they cannot be sure which way birth rates will go in the future. The UN report also notes that AIDS has increased death rates and slowed population growth in 60 countries. The area most affected by the disease is Southern Africa. There how long people live has fallen from an average of 62 years in 1995 to 48 now. Researchers believe life expectancy will fall to 53 years by 2015, then begin a slow recovery.

This VOA Special English Development Report was written by Nancy Steinbach . I'm Gwen Outen.