A report by MIT Technology Review, based on the data collected from multiple sources, said at least 66 zero-days have been found in use in 2021, which is almost double the number of such attacks recorded last year. It blamed government-backed hackers for the rapid rise in such attacks.

source https://gadgets.ndtv.com/internet/news/zero-day-hacking-attack-2021-record-unprecedented-mit-technology-review-2551866#rss-gadgets-all