LONDON -- The population of Iran will be 105 million in 2050 with people living longer and having a median age of 40 years old, twice the current average, according to the latest revised figures from the UN Population Division.

The rise in from the current population of 20m is at a lower rate than the increase to 121m projected by the UN last year and is in line with a 400m reduction in the estimated global population to 8.9 billion by the middle of the century.

Over the next 50 years, Iran is expected to move up from 17th to 16th in a table of the world's most populated countries. In the process the number of Iranians will overtake the declining populations in Germany and Russia, but not Japan as earlier forecast.

Life expectancy of people living in Iran is also projected to increase from a current average age of 70 to 79 years old by 2050. At the same time, infant mortal rate is expected to be slashed from 33 to nine per 1,000 live births.

The most marked change, as elsewhere in the world, will be in the demographic make-up of Iran. The current 35.2 percent of children under the age of 14 as a proportion of the population will be halved, while the number of people over 60 will rise fourfold to 25 percent.

The UN report 2050 World Population Prospects: The 2002 Revision suggested that the highest population growth would be in India, with the number of people rising by 50 percent to 1.5bn and overtaking China as the world's most populated country.

The next highest growth rates were expected in Pakistan, Nigeria and Ethiopia, moving up to 4th, 6th and 9th respectively among the highest populations.

The downward revision in the world's population was accounted for by lower fertility rates expected in the future and an increase in the number of deaths, primarily from AIDS.

Future fertility rates were projected to fall to be below the replacement level of 2.1 children per women in most developing countries at some point in the 21st century.

While many developed countries were expected to experience declining population, in some like Britain and the U.S., increases were forecast partly as a result of immigration.

The United Nations lowered by 400 million the global population projections it made two years ago, reflecting a higher death rate due to HIV/AIDS and a reduction in fertility levels, said a United Nations Information Center in a press release here on Thursday.

A report released Wednesday by the Population Division of the UN Department of Economic and Social Affairs (DESA) projects that by 2050, there will be 8.9 billion people globally, a drop from the 9.3 billion previously stated in its 2000 forecast.

The report attributes the lower figure in part to a worsening of the effect of the HIV/AIDS epidemic in terms of increased morbidity, mortality and population loss. Although the probability of being infected by HIV is assumed to decline significantly in the future, the long-term impact of the epidemic remains dire, with 278 million more people expected to die of AIDS by 2050.

"HIV/AIDS is a disease of mass destruction," Joseph Chamie, director of the Population Division, said at a press briefing at UN Headquarters in New York to launch the report. He added that the deaths due to the AIDS epidemic were many times greater than any military conflicts in the past 10 years.

The report also states that despite the devastating impact of the HIV/AIDS epidemic, the populations of the affected countries are generally expected to be larger by mid-century than today, mainly because most of them maintain moderate fertility levels. (IRNA)