http://www.who.int/whr/2001/media_centre/press_release/en/ http://www.who.int/whr/2001/media_centre/press_release/en/ http://www.who.int/whr/2001/media_centre/press_release/en/ http://www.who.int/whr/2001/media_centre/press_release/en/ http://www.who.int/whr/2001/media_centre/press_release/en/ 1 in 4 people http://www.who.int/whr/2001/media_centre/press_release/en/ 1 in 4 people 1 in 4 people roughly one-quarter 450 million roughly one-quarter