So, through January 1st:

1. Sasse (Senate)

2. Menendez (Senate)

3. Helmy (Senate)

4. Cicilline (House)

5. Stewart (House)

6. McCarthy (House)

7. Johnson (House)

8. Higgins (House)

9. Buck (House)

10. Gallagher (House)

11. Gaetz (House)

12. Kim (House)

13. Schiff (House)

14. Armstrong (House)

15. Jackson (House)

Exactly 15 isn't over 15.

But then there's González-Colón, Puerto Rico's "Resident Commissioner", who resigned January 2nd.

So . . . is Puerto Rico's Resident Commissioner, for purposes of this question, a member of Congress? Such a person gets to vote in committees, have floor privileges, can introduce legislation, and draw a salary, but they don't have a floor vote. Wikipedia classes them as a "Non-voting member".

If yes, this question resolves YES. If no, and there's no new last-minute resignation, this question resolves NO.

The description stated that the source is the Wikipedia article, which includes González-Colón. Wikipedia classifies her as a "member" as well, like you said.