These numbers are from a Pew Research survey, "MIXED REACTION TO POST-SEINFELD ERA," dated May 10/11, 1998.* The number before each show name is the percentage of respondents who identified the show as their favorite ever sitcom just before the 1998 Seinfeld finale. The number after each name is the percentage for each show just before the 1993 Cheers finale:

14 Seinfeld 2
6 M*A*S*H 8
5 Home Improvement 4
5 Cosby Show/Cosby 9
4 I Love Lucy 4
3 Friends —
3 Cheers 10
3 Frasier —
2 All in the Family 4
1 Andy Griffith 2
1 Roseanne 4
27 Others 27
26 None/Don’t have a favorite/Don’t know/Refused 26

One thing that's interesting is that the older shows all declined over the five years - except Lucy. She defies gravity.

*The full pdf is at the bottom of this page: https://www.pewresearch.org/politics/1998/05/10/mixed-reaction-to-post-seinfeld-era/