Yesterday we took a look at the scoring defense that was the foundation of the Alabama Crimson Tide's 2011 National Championship campaign. Today we'll look at how this unit's overall defensive numbers stack up against against the competition and their historical predecessors.

Last season Alabama lead the nation in rushing defense, passing defense, total defense and scoring defense. The 77.9 yards per game gap between No. 1 Alabama and No. 2 LSU in total defense is the largest ever, reported ESPNs Brad Edwards.

Here is a list of the college football teams that allowed the fewest total yards per game each season since 1989 (the farthest back the NCAA has statistics available online):

College Football Total Defense 1989-2011

Data available here

Alabama's 2011 defense is clearly far beyond the rest of the pack in the time frame shown. In the past 23 years, it is the only defense to allow less than 200 yards-per-game over the entire season (183.62 ypg). The 1986 Oklahoma defense did surpass this mark allowing a mere 175.5 yard per game but without access to NCAA numbers I was unable to determine if any teams accomplished the feat in 1987 and 1988.

Since at least 2000, no other team has lead the nation in both rushing defense and passing defense like Alabama did this year. The key to that performance was the Crimson Tide's pass defense which allowed just 111.46 yards per game in the air, the lowest total for at least the past 11 season.

So, now let's see how the 2011 defense stacks up against the Crimson Tide's previous national champion squads. The Roll Bama Roll spreadsheet of Alabama defenses only has yardage numbers going back to 1961 so this comparison only examines the teams since that season.

Total Defense for Alabama's National Champions since 1961

Data available here

Rather well, actually. Only two of Alabama's national championship squads permitted fewer yards than the 2011 unit; the amazing 1961 crew (135.45 ypg) and the oft-overlooked 1979 team (163.25). Outside of those three, every Crimson Tide title defense - including the famed 1992 team - were over the 200 ypg mark.

So, how does this team stack up against every Alabama defense over the past half-century? Even better than we saw yesterday with scoring defense.

Alabama Total Yards/Game Allowed 1962-2011

Data available here

Unlike the comparison of scoring defense yesterday, there seems to be a consistency in the total defense numbers across the decades. It's not difficult to pick out the quality years and the ones where Alabama was struggling (again, the 1968-1970 nadir of Bryant's tenure simply jumps out in this representation).

The 2011 Alabama defense is actually fourth in total yards allowed when compared to Crimson Tide squads since 1961. It is eclipsed only by the 1961national championship squad and the unfortunate 1962 team (which found itself out of both the SEC and national championships following a 6-7 defeat at the hands of Georgia Tech in Atlanta).

And while the total yards allowed seems to correlate much better with the particular teams that succeed in claiming the conference and national crowns, the ability to do so unscathed is very remote. Only four of the Alabama's most stingy defenses since 1961 were able to go wire-to-wire on the season and one was unfortunate enough to stumble twice.