North Korean mortar fire caused 80 percent of the casualties.

And cigarette smoking is known to cause 85 percent of all lung cancers.

Worldwide, viruses are estimated to cause 15 to 20 percent of all cancers in humans.

Few people dispute that these accidents cause 15 percent to 25 percent of all child deaths in urban areas.

Getting hit by the backpack caused 13 percent of the injuries.

It causes 5 to 20 percent of sore throats in adults.

During the 1980 campaign, he asserted that trees caused 93 percent of the nitrogen oxides in the atmosphere.

In 2000, the last year for which statistics are available, 160 children choked to death, with food-related items causing 41 percent of the cases.

Some studies estimate that fertility treatments have caused 60 percent to 80 percent of the increase.

And smoking causes 87 percent of all lung cancers.