In WWII, men averaged 10 days a year in combat, in Vietnam men averaged 240 days a year in combat.
Source: the movie "Vietnam in HD"
My jaw dropped when I saw this. I have a day off work, and I am spending some time with this movie. I am currently in the year 1966-1967. Kids are at school, and I can fully engross myself in the movie, the stories, the men and the families, it's an incredible accounting of the war.