Desertion lower than Pre-Iraq War

Statistics are from this Strategypage article:

1999-2,966

2000-3949

2001-4597

2002-4483

2003-2771

2004-2357

2005-2543

2006-3196

The writer claims that the decline is because of better screening of recruits by Pentagon officials, but could it also be due to a little known phenomenon called "patriotism"?