I've noticed that, just by chance, every few decades of game time, a particular random event occurs several times in rapid succession. This isn't necessarily unrealistic, but can get pretty annoying for a player if it's an event that takes a while to recover from, such as "Pretender to the Throne", "Wave of Obscurantism", "Temporary Insanity of Monarch", "Political Crisis." I've seen each of these, just by chance, occur 3 or 4 times within a single year. Is there any global parameter that reduces the chance of any random event re-occurring if it happened recently?