In the US, a reasonable estimate is dozens of murders per year. I don't know if we can do any better without running a study: There's no good data easily available; the murder clearance rate in the US is now quite low; most insurance killings are, of course, staged to look like accidents.
But it's enough of a problem that there are quite a lot of legal journal articles about it, e.g.: https://scholarship.law.campbell.edu/cgi/viewcontent.cgi?art...
Life insurance has killed a lot of people. People who would otherwise be alive but for the existence of payouts upon their deaths.
Sounds like insurance companies aren't profit maximising enough!
If I sign up for a big life insurance, those guys better give me a body guard and a food sniffer to protect themselves from a big payout.
Do you have any data on how much of a problem that is?