Missing an episode - should be 22 in the season.
Average rating of the 21 regular episodes in this season: 7.38095238(some databases, including NBC's VOD platform, include the special episode "Olympics" at the beginning of season 2)
I'm going to round up this time. I actually really enjoyed this season, even if I didn't laugh a whole lot or give individual episodes particularly high ratings. Sticking it out this long was definitely worthwhile.