I don't have good numbers, but it's likely less dangerous than you think it is. The vast majority of what an infantryman does falls into two categories - training, and waiting. And that's a boots on ground, rifle in hand category - there's a bunch of rear-echelon ratings as well.

I'm guessing that it's likely within an order of magnitude of danger as commuting to work. Likely safer than delivering pizzas. There's probably a lot of variance between specific job descriptions - a drone operator based in the continental US is going to have a lot less occupational risk than the guy doing explosive ordnance disposal.