A football fan — or an NFL executive — would like to think the Patriots going for perfection against a team from New York can beat both 49.1 and maybe even the 78 share. After all, we’re talking about something that’s never been done — not only a perfect season, but one with two more victories than the only other perfect season in league history, authored by the 1972 Dolphins.

But perfection isn’t what sells football games. Those Dolphins, despite considerable star power, managed a modest 41.6 rating — the worst rating in the 18 Super Bowls played from 1972-89 — and 73 share. Put that against the Cowboys, whose lowest rating ever was 44.2 and who remain the league’s biggest national drawing card.

Since 1996, just three Super Bowls have had a rating better than 45, and all three involved the Cowboys — in 1993-94, both games against the professional bridesmaid Bills, and in 1996 against the Steelers.

After the Cowboys, the best-rated Super Bowls in the past 20 years both involved the Packers, in 1995 against the Patriots and in 1996 against Denver.

Even the bad numbers are truly amazing and all the proof you need that the Super Bowl is the greatest sporting event this nation has ever seen. Even today, with hundreds of channels to choose from, on Super Bowl Sunday you can bet the ranch that at least 40 percent of the nation’s televisions and 60 percent of the total television audience will be watching the game.

But the audience has become almost static. Since 1990, when the Washington Redskin’s win over the Buffalo Bills drew a 39 rating and a 63 share, no game has had a rating lower than 40.2 nor higher than 46.1, while the share has ranged between 61 and 72. Of the 17 games between 1991-2007, 11 drew shares in the 61-63 range, and 13 drew ratings between 40.2 and 43.3.

So there’s a lot of inertia built into the system; the audience is pretty well established, and you have to offer something really special to bump it.

The ratings for the playoff rounds and for the Pats’ big games against the Colts, the Cowboys and the Giants suggest that New England has built up some juice. And, while the Giants don’t draw like the Steelers, Packers and Cowboys, they still do a little better than average.

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But big regular season games are watched mostly by football fans, and the Super Bowl relies on crossover appeal to generate truly huge numbers.

Is perfection and Brady and a Manning enough to do that? Is it enough to get a 50 share?

My guess is that the game will break a 45 and maybe hit 47, which would make it the biggest game since 1982. But I don’t think it will set a record. For that, you need the Cowboys — and a lot more personality than these two teams can muster.