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 six thousand five hundred million this July. By the middle of the century, the population could reach more than nine thousand million. That would be an increase of forty percent.

These numbers are fresh estimates for a report on world population change from nineteen fifty to two thousand fifty. Hania Zlotnik is director of the U.N. Population Division. She says the world has added nearly five hundred million people in the last six years.

But, in her words, "the good news is that new estimates show that it will take a little longer" to add the next five hundred million. Mizz Zlotnik says this will probably happen by two thousand thirteen.

The U.N. report says most population growth by two thousand fifty will take place in less developed countries. Their population is expected to increase from five thousand million today to almost eight thousand million. The population of more developed nations is expected to stay about the same, at just over one thousand million.

The report says nine countries will be responsible for about half the world population increase by twenty fifty. These include Bangladesh, China, the Democratic Republic of Congo, Ethiopia and India. The others are Nigeria, Pakistan, Uganda and the United States.

Twelve 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.

The report says birth rates remain low in forty-four developed countries.

Today, worldwide, there is an average of two-point-six children per woman. This number is expected to fall to just over two children per woman in two thousand fifty. But U.N. population experts note that they cannot be sure which way birth rates will go in the future.

The U.N. report also notes that AIDS has increased death rates and slowed population growth in sixty countries. The area most affected by the disease is Southern Africa.

There, how long people live has fallen from an average of sixty-two years in nineteen ninety-five to forty-eight now. Researchers believe life expectancy will fall to forty-three years by two thousand fifteen, then begin a slow recovery.

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