ORIGINAL: Bob H in NH
I bet over 50% of the deer die from "non hunting" deaths, these include, disease, coyote, old age, cars, injuries from fights.
Check this study in Idaho. Only two years so far, but they're finding some interesting stuff. Verifies what you're saying.
Also, in Montana at least, winter can be highly variable. In 1998 in western Montana, winter reportedly killed 60% to 80% of the whitetail herd. Big snows hit right before the rut and trapped deer from moving. With the mildwinters we have been having, probably not many die due to weather.
http://fishandgame.idaho.gov/cms/wildlife/manage_issues/ung/