world population increasing

By the Numbers:

9.1 billion = Projected world population in 2050
2.5 billion = Projected population growth in world's poorest nations from 2005 to 2050

394 million = Projected U.S. population in 2050
298 million = U.S. population in 2005

''It is going to be a strain on the world,'' said Hania Zlotnik, the division's new director. She said the expected growth will be concentrated in countries that already struggle to provide adequate shelter, health care and education.