Military demographics

As an old infantryman, I was outraged to read that
... Iraq has been declared a no-booze zone, and troops face harsh punishment if caught drinking.

Does this have something to do with legal drinking ages and Army demographics, I wondered. The same article says,
According to Pentagon statistics, only 6 percent of regular Army troops are older than 40, compared with 22 percent of Guard members.

The idea of fighting a war with 94% kid power seems like a fantasy novel premise, so I consulted my Civil War stats. Unfortunately, Ages of U.S. Volunteer Soldier, U.S. Sanitary Commission is not available on the Web in its entirety, but this fragment tells a story different from the Iraq war demographic:
The various breakdowns of age for the Federal Army during the Civil War:

• Age 13 = 127
• Age 14 = 330
• Age 15 = 773
• Age 16 = 2,758
• Age 17 = 6,425
• Age 18 = 133,475
• Age 19 = 90,215
• Age 20 = 71,058
• Age 21 = 97,136

From there it gradually goes down to the following;

• Age 45 = 7,012
• Age 46 = 967
• Age 50 and Over = 2,366

The missing piece in this quote is the 22-44 age range and that range seems to hold the bulk of the force. I think I can safely infer that the Civil War force structure contained well over 6% in the 40-and-over age range.

All this resonates with me because I have been reading a book where the "modern" (WWII) radically overlays the "old" (Civil War): Across the Dark Islands. It's the story of a National Guard officer (read US Volunteer) assigned to a National Guard regiment not from his state in a division dominated by Regular Army regiments. In other words, a man is fighting a war in personal "goat" status in a unit with Army "goat" status in a "goat" theatre.

Perhaps there are some things worse than being in a war zone booze free and under 40.