Very funny that the Times was so certain about the panic they were causing that they set up a little live update election-season scoreboard for it.
https://subium.com/profile/iboudreau.bsky.social/post/3kwsswu7qgi2q
https://www.nytimes.com/interactive/2024/us/elections/biden-drop-out-democrats.html
According to another source it's at least 10 of 213 reps.