The U.S. Department of Defense has to recruit 180,000 new people this year, to replace those who are retiring, completing their enlistments or were killed or disabled by  combat or accidents. These 180,000 new people will keep the 2.5 million strong (active and reserve) force up to strength. Casualties from fighting in Iraq and Afghanistan make up a very small portion (about 3,000 dead and badly wounded) of the replacements needed. But the prospect of being sent off to Iraq has caused some reluctance to enlist. Hurting even more, though, is the stronger economy and lower unemployment rate. The army has been hurt the worst, as it is obvious that most of the combat troops in Iraq are from the army. So the army has, as it had to do during the economic boom of the late 1990s, lower its standards a bit. Thus this year, ten percent of recruits can get in without a high school diploma, and two percent of those with borderline aptitude test scores will be let in, compared to 1.5 percent last year. Over all, those with no high school diploma, or low aptitude test scores, are more likely to flunk out of basic training, or later training. Some of these troops do very well, but the statistics are against them. When the army has fewer better qualified candidates, it gives more of the borderline prospects a chance. This costs more money in the long run, but does get the needed people. 

More troops have been assigned to recruiting duty, and more signing bonuses are being offered. Theres also more advertising and other promotion. Thus the military is spending, on average, $14,500 to obtain each new recruit.