Because people with IQs below 80 (the 10th percentile, Department of Defense "Category V") are difficult to train, federal law bars their induction into the military. As of 2005, only 4 percent of the recruits were allowed to score as low as in the 16th to 30th percentile, a grouping known as "Category IV" on the U.S. Armed Forces' mental-aptitude exam. During the Vietnam War, a program known as Project 100,000 was devised to recruit much more heavily from this category, but was eventually ended in 1971.