“The last time the U.S. had a full House — with all 435 of its voting representatives seated — was nearly three and a half years ago. And even then, it wasn’t full for long. When Wisconsin Rep. Sean Duffy resigned on Sept. 23, 2019, to care for his newborn baby with a heart defect, he left a House that had had 435 members for all of six days. In the 1,261 days since, there’s been at least one empty seat in the House.”
https://fivethirtyeight.com/features/house-435-members-pretty-rare/