Defense in a Passing Era

One of the most amazing stats I've ever heard was a few years ago when I learned that every single SB winner dating back to 1979 or so had a top ten defense. I know that the Indy Colts recently broke that trend, so I was curious to see where the current final four teams ranked during the regular season on defense. I sorted NFL.com by points against (Giants, btw, were ranked 17th):1 Pittsburgh Steelers2 Green Bay Packers3 Baltimore Ravens4 Chicago Bears5 Atlanta Falcons6 New York JetsYear in, year out, the majority of the teams that make the playoffs (no less go all the way) rank within the top ten on defense.