Charles de Gaulle survived 31 attempts. https://www.amazon.com/Target-Gaulle-attempts-French-preside...
By all accounts he was a bit of a jerk, but he dressed well and wasn't afraid to fire back, so you have to give him some credit.
Our current world existing is sensitively dependent on Hitler not being assassinated. Universes where Hitler is killed early result in nuclear annihilation for some reason, and the only Everett branches that have humans in them have an improbable history of a single man dodging dozens of assassination attempts
what if time travel does exist, and allowing Hitler to live was the least bad option for the world? i.e. if Hitler was killed early in the war, he wouldn't have been able to override his generals with so many stupendously stupid ideas.
In the end this is just a variant of the "If there's a God why does it let bad shit happen" question.
It's more likely that there are eldritch Lovecraftian entities feeding upon sentient misery.
There is a chance of success based upon relevant stats and traits and one of the outcomes is that failed assassination attempts often result in them becoming harder to assassinate as they take more precautions and occasionally show mental side effects.
Now look at Fidel Castro and the clownish job of the CIA's loony toons assassination attempts.
It sounds absurdly gamey at first but assassination resistance may be effectively trainable like immune systems or antibiotic resistance. There is nothing magical about it - the target simply builds up infastructure of countermeasures, deliberately not following schedules, and less physically accessible to anyone unvetted. If in the dirty business of sending assassins in the first place quantity does not have a quality in its own but makes defenses stronger - strategically what is needed is one to do it right.
"Stop sending people to kill me! We’ve already captured five of them, one with a bomb and another with a rifle… If you don’t stop sending killers, I’ll send one to Moscow, and I won’t have to send another"
Though I'll concede that having the list for him and not others does point to more attempts...
estimated the number of assassination schemes or actual attempts by the Central Intelligence Agency to be 638
(according to the Church Committee)
But most of these cases are still shrouded in the veil of secrecy by the intelligence agencies, so there is still a lot of guesswork and substantial amount of secret records involved.
The best trawl through this marterial is the gargantuan (but highly readable) "The Rise and Fall of the Third Reich" by William Shirer, an American journalist living in Europe during Hitler's rise to power and the second world war.
If you are interested in result of going through all that material, read Richard Evens trilogy.
But thank you for the other recommendation.
The last couple of panels have them saying something like "
It's an OK job but what's the deal with all these time travelers coming to kill the guy we're guarding - this is the third one this week!"