To understand just how good the NFL's ratings have been this season — the best in about 15 years — it helps to take a moment and compare the league to the rest of TV.

Games on CBS, Fox and NBC averaged 20 million viewers. The average for the prime-time programming on the four major networks, the most coveted slots on the schedule? Around 8.2 million viewers.

That means NFL ratings are 144 percent better than television's top non-football lineups, and here's the kicker. That difference was 61 percent just five years ago.

Even CBS Sports president Sean McManus, whose network has committed billions of dollars to broadcast the NFL, is wowed by the figures.

"I'm continually pleased and really amazed by the kind of ratings that are being generated by all the networks during the regular season and postseason," McManus said on a recent conference call.

"Go figure," he added. "The NFL is just on fire this year. Fan interest seems to be at an all-time high."

Fox Sports chairman David Hill this week ticked off the many theories for the league's success. More knowledgeable fans. The prevalence of high-definition television, which particularly benefits NFL games. The recession, which has kept more people at home.

The ratings were already strong last season, then took another jump this year. Stars and story lines have lured in viewers, with a deep list of big-name quarterbacks playing well — or at least making news, in the case of Minnesota's Brett Favre. Appropriately, two franchises whose traditions tend to draw big ratings — Green Bay and Pittsburgh — are in the Super Bowl.

"The secret weapon is Howard Katz, the NFL's scheduler," Hill said. "If you're not getting the right matchups in the right markets, then you are not putting the most appealing thing in front of people. If you look at the matchups he's put together week in and week out and year in and year out, his hard work is shining."

The soaring ratings stand in contrast to a rough year off-the-field for the NFL. That includes scandals involving two of those big-name quarterbacks — Favre, accused of sexting a Jets employee in 2008, and Super Bowl-bound Ben Roethlisberger, who was accused of sexually assaulting a college student in Georgia though prosecutors declined to press charges. Both men were punished by the league. Roethlisberger had to sit out the first four games of the season and Favre was fined $50,000 at the end of the year.

Clearly the negative attention hasn't hurt, and maybe it even stokes interest.

McManus believes the salacious stories do sometimes attract more viewers initially, but they won't stick around if the on-field product isn't good.

And there's the twist. Just when NFL fans seemingly can't get enough of football, the Super Bowl may be all they're getting for a while. Among the negative off-field dramas is the wrangling over a new contract between owners and players that might lead to a lockout.

McManus predicted little lasting impact on ratings as long as a lockout didn't result in a large chunk of the 2011 season being canceled.

Hill was more pessimistic.

"With the sport reaching heights that Pete Rozelle would never dreamed of, we want to keep it that way," he said. "We know what happens to sports after a strike or a lockout; people turn away and it takes a while for them to come back. It would be a great tragedy if both sides weren't able to reach an agreement."

The union uses the record viewership as evidence the league is doing just fine financially and doesn't need to redistribute revenue — and that the timing is risky for a work stoppage.

Steve Solomon, a former ABC and NHL executive who works as a media consultant, said the amount of revenue a league can bring in from TV doesn't affect the major debates of a labor negotiation.

"Regardless of how much money there is in this pie, there's the same issues that are going on in the NBA in their negotiations and what went on with the NHL in their negotiations," he said. "Whatever the pie is, it is about whatever is the fairest way to split it up."