The U.S. Army has discovered that their biggest Internet vulnerability is servers that have not had their software patched. Some 98 percent of successful break ins of Army computers are the result of hackers taking advantage of know weaknesses that could have, and should have, been fixed. Despite that persistent problem, which is one of recruiting Internet savvy troops, or being able to train them quickly enough, the army has improved it's Internet defenses. In 2001, for every thousand attempted Internet break ins, 6.69 were successful. In 2000, there had been 11.6 break ins per thousand attempts. Very few of the break ins of military web sites have been serious, because the most critical military computers tend to be better protected. But there is, obviously, risk.