alt Hacker News"Four times every two years" isn't exactly the same as "twice every year", but also reflects a similar, "not that unusual" answer.
Although I didn't claim "twice every year like clockwork" in my top-level comment either. It's just a very basic statement of the base rate.
Make it eight-times every four years or sixteen-times every eight years. Or maybe "Four-times every other year, in a clustered fashion".
I don't think any of that really changes the point.
It does change the point! If it happened roughly twice a year, it's not as noteworthy when it happens than if tends to happen every other year, but four times.
It's more noteworthy when it happens the more clustered it tends to be. If it were typical that we'd go ~7 years with none then have ~16 in a single year, it would be huge news when it happens.