I've done a lot of walking in my life, I've stepped in a lot of puddles, been splashed with muddy water by passing cars, and gotten lots of snow in my shoes, been stopped by police and by drunk people. And that's not counting the rough terrain, that's just normal old sidewalks. During a single season, I would end up making over a hundred walks, and I would end up facing trouble at least a handful of times. Not all abysmal failures are necessarily matters of life and death, sometimes they can just be frustrating.
Those hospital statistics were per stay, collected on patient discharge. It was explicitly not per year.
I didn't know that the revised rules had rules for contraceptives, I can't really comment on that in particular. Although, if I were using 200 year old contraceptives, I would imagine the failure rate would be higher than what is printed on the box. Same goes for 200 year old bullets. It's kind of amazing they work at all, really. I remember that time some guy found a box of 100 year old munitions, and the bomb squad had to come out and take care of it, the result was underwhelming to say the least.
In any case, computer simulations may be driven by advanced mathematics and probabilities, but narrative is driven by dramatic tension and character interest. So from a perspective of interest, something that is subjective, the time and effort to roll dice is well spent when it involves risk, suspense and decisive outcomes. (One does not roll dice to pull a trigger, roll dice to ignite the primer, roll dice to eject the casing, and then roll dice to load the next round. There is already some level of aggregating built in.)
If anything, I would recommend having more degrees of success or failure for allowing finer control depending on the circumstances, rather than going for a binary yes or no.
