Past 5 years plus this current year is a fair sample size, no?
Includes regular season and playoffs, updated as I post this:
1. New England 75.7%
2. Indianapolis 67.0%
3. Pittsburgh 66.7%
4. Green Bay 64.9%
5. San Diego 63.9%
6. New Orleans 62.5%
7. Baltimore 62.2%
8. NY Giants 61.1%
9. Dallas 59.8%
10. Chicago 59.6%
11. Philadelphia 56.8%
12. Tennessee 54.9%
13. Atlanta 53.8%
14. NY Jets 53.6%
15. Houston 48.9%
16. Minnesota 47.9%
17. Jacksonville 46.7%
18. Arizona 46.3%