I can't remember the statistics, but one of the reasons the American bomber crews were given tours of 25 missions (reduced from the original 30) is that when multiplied by 30 missions, the risk of being shot down reached 100%.
Now of course, the Axis forces don't get or deserve quite the same sort of sympathy, but statistically the most dangerous assignment of any nation on any front was the German U-boat crews. 75% of them were killed. If you've never seen the film Das Boot it's a good one. You can literally feel the terror of a cramped submarine taking on water and being depth charged for hours on end.