As Cesar's stats indicate, getting killed by a venomous snake in the USA is incredibly low. Rattlesnakes have evolved to kill rats, ground squirrels and maybe something as big as a rabbit. Weighing 50-90 kgs instead of 0.5 to 1 kg means it is only the exceptional incident (multiple bites, small child, the elderly, a bite in a vunerable location, great distance from help, and typically 2 or 3 of those factors) that kills a human. So snake bite is down in the weeds of the statistics with bear and shark attacks. Front page news when it happens, but an insignificant risk. Well below lightening (23 so far this year), small-plane crashes (a few dozen this year in my state alone) much less risks that actually add up - exposure for hikers, slips/trips/falls around the house, and motor-vehicle accidents for everyone.
That doesn't mean those thousands of non-fatal bites don't hurt A LOT. A park ranger / naturist / snake handler I'd bring in for Wilderness First Aid classes recounted his experience getting bit. He'd reached into a cage to get something, quickly enough he thought, and got bit. He said he had about 1-2 seconds of thinking "Damn, that was stupid of me!" before his over-riding thought was of the intense pain. (They don't inject just poison, but also digestive enzymes to break-down the rabbit from the inside.)
The take-home message (other than "don't reach into cages containing rattle snakes) is, "If you're bit and poison was injected you WILL know." That is lacking in most first aid books which try to describe the bite patterns of poisonous and non-poisonous snakes. So what?, it might have struck at you and not hung on long enough to inject. But if you have poison in you, you WILL know it.
Every time I've approached a rattle snake (while on staff at a Scout Camp, I'd relocate any that were seen to outside of the camp), they take every opportunity to escape and avoid the humans.
Anyone who worries about snakes in sleeping bags or what caliber gun to carry for grizzlies without first getting the very best tires, brakes and airbags on their car needs to have a better grasp of statistics and basic math.