Bank on it: 49ers heading south in 2012

The San Francisco 49ers are coming off a 13-3 season. They have re-signed key players, added a few new ones, and set themselves up for another successful season.

Doesn't matter.

They're going down in 2012. Recent history tells us so, anyway.

Nineteen NFL teams won at least 13 games in a season from 2004 through 2010. All 19 finished with fewer victories the following season. The drop was 4.1 victories per team on average, from 13.5 to 9.4. The 2003 and 2004 New England Patriots were the most recent team to win at least 13 games in consecutive seasons. They went 14-2 both times.

Of course, there are only 16 games in a season. The better a team fares one season, the less potential for improvement exists in the following one. At a certain point, there is almost nowhere to go but down. The 49ers approached that point last season. The math is working against them in 2012.

Sixty-one teams have finished 13-3 or better since the NFL adopted a 16-game schedule in 1978, according to Pro Football Reference. None finished with a better record the following season. Five finished with the same record:

The current 49ers can still win the NFC West in their second season under coach Jim Harbaugh. They can still win in the playoffs. But if they finish the 2012 season with 13 or more victories, they'll be breaking from a strong trend. Recent history suggests the 49ers should be thrilled to finish even 10-6 or better this season.

Thirteen teams have gone 13-3 since 2004. Those teams won 8.3 games on average the following season. Only three finished better than 9-7: The 2007 Indianapolis Colts ((12-4), the 2009 New Orleans Saints (11-5) and 2010 Atlanta Falcons (10-6).

Green Bay, New England and New Orleans joined the 49ers at 13-3 or better last season.

The chart shows what happened to teams finishing 13-3 or better since 2004.

2004-2010: Teams with 13+ Victories