Which Have Been the Best and Worst NFL Teams Over the Last 10 Years?

Over the last 10 NFL seasons (2003-2012), only six teams have won at least 60 percent of their regular-season games:

Patriots (78.8 percent)
Colts (70.0 percent)
Steelers (64.4 percent)
Packers (61.3 percent)
Ravens (60.6 percent)
Chargers (60.6 percent)

Together, those teams have won 7 of the last 10 Super Bowls.  The other three titles were won by the Saints (2009) and the Giants (2007 and 2011).  Only the Chargers have won over 60 percent of their games over the last 10 seasons without winning the Super Bowl.

Over the same period, five teams have won less than 40 percent of their regular-season games:

Bills (39.4 percent)
Rams (35.3 percent)
Browns (32.5 percent)
Raiders (30.6 percent)
Lions (30.0 percent)

By the way, the Chiefs, Redskins, and Dolphins all went 68-92 from 2003 to 2012.  That's a winning percentage of 42.5 percent.