For the answer to this question, let’s look back at a few recent seasons:
2019: Favorites 1481-985 (.601)
2018: Favorites 1442-1022 (.585)
2017: Favorites 1405-1063 (.569)
Favorites have won between 57-60% of games. The exact number will vary by season. Also, keep in mind that the payouts on big moneyline favorites can be less than stellar, so blindly betting on favorites doesn’t necessarily mean you’ll come out ahead for the season as a whole.