WASHINGTON — The world's poorest countries have one thing in ever greater abundance — people.

"Nearly all of world population growth is now concentrated in the world's poorer countries," said Bill Butz, president of the Population Reference Bureau, an independent research organization.

Currently 1.2 billion people live in countries classified as developed by the U.N., compared with 5.5 billion in less developed regions, PRB said in its annual Population Data Sheet.

There is little growth — even decline — in the richer countries.

"And by 2050, global population is projected to rise to 9.3 billion. Between now and mid-century, these diverging growth patterns will boost the population share living in today's less developed countries from 82 percent to 86 percent," said PRB demographer Carl Haub.

Some other findings from the data sheet:

• Some 35 percent of the population in the least developed countries is undernourished, and that rises to 60 percent in some sub-Saharan countries.

• One in 75 women died of pregnancy-related causes in less developed countries. In developed countries, the rate of maternal death is one in 6,000.

• Lifetime fertility is 5.4 children per woman in sub-Saharan Africa and 4.7 in the least developed countries. In the developed countries, women average 1.6 children.

• Sometime this year the world will have an urban majority for the first time, with more than half of the people living in cities.

On the Net:

Population Reference Bureau: www.prb.org