Previously I had seen 95% somewhere else but cannot find the link, but that's close enough.
The reason why this is credible is Iran is limited by its amount of launchers, and Israel is very effective at destroying these. With complete air superiority and drones flying over, it's very easy to spot the heat signature for a launcher.
Add to that the launchers that were effectively buried at the start of the war when the openings to Iran's underground missile storage facilities were bombed.
https://understandingwar.org/research/middle-east/iran-updat...