You might want to check out this article also for some more detailed info on those numbers.

Note the desertion rate was similar in 2001 & 2002 (before the war) to what it was this past year. Then in 2004 it dropped in half. Seems it has just returned to prewar numbers. The Marines numbers continue to be below pre-Iraw war numbers.

Finally, they start thinking for themselves rather than blindly following orders.