HOLLYWOOD — The nets scrap and claw for every fraction of a demo ratings point all season, and then in one harried week, they cash in their tickets.

When the upfront dust settled at the end of May, the clear winner — aside from broadcast television in general — was NBC.

According to a consensus of reports, NBC became the first net to reach the $3 billion mark in secured advertising revenue, and the six broadcast nets combined to top $9 billion for the first time.

The Peacock was followed in sales coin by CBS ($2.2 billion), ABC ($1.7 billion, not including “Monday Night Football”), Fox ($1.6 billion), the WB ($710 million) and UPN ($240 million).

These upfront estimates are Madison Avenue’s grades on the nets’ performance during the most recent season as well as their take on the nets’ potential for the upcoming one.

The figures offer a powerful argument for why the 18-49 demo is the best indicator of a net’s ability to generate ad revenue — and why execs at ABC, NBC and Fox focus on little else when analyzing ratings performance.

For the season, NBC led primetime in adults 18-49 with a 4.5 rating/12 share, powered by television’s top-rated comedy (“Friends”), drama (“ER”) and newsmag (Tuesday’s “Dateline”).

On a per-hour basis, the net commanded an industry-best $136 million ($3 billion for 22 hours), followed by Fox’s $107 million (for its 15 hours), CBS’ $100 million, ABC’s $77 million (plus “Monday Night Football”), the WB’s $55 million and UPN’s $24 million.

This order is the same as Nielsen’s final adults 18-49 standings for the 2002-03 season. (CBS and ABC tied for third, but the Alphabet’s average was inflated by the Super Bowl.)

While Nielsen’s rankings by “households” and “total viewers” are easier for most people (and consumer publications) to get their arms around, the 18-49 demo category is a much better indicator of revenue potential. And isn’t this what the television business is all about?

This is not to say that factors other than 18-49 delivery aren’t important. The WB, for example, sells much of its time on the hard-to-reach (and thus lucrative) 18-34 demo, and CBS sells some programs on 25-54, where it performs better.

Also affecting revenue totals is a net’s ability to attract upscale viewers: In these categories, NBC and CBS (which have stronger scripted series) are well ahead of Fox and ABC (which are more dependent on unscripted skeins).

In the business of television, however, advertising revenue isn’t everything. Profitability matters, too.

Compared with NBC, CBS spends considerably less on its big Monday and Thursday 18-49 hits — although a recent contract extension makes the Eye’s “Everybody Loves Raymond” much more expensive. The Peacock’s “ER” and “Friends” are the most costly skeins in primetime, and “The West Wing” and “Frasier” are veterans that come with steep pricetags even as their ratings slide.

Any primetime profit story must also include the millions and billions ABC, CBS and Fox shell out for pro and college sporting events.

NBC, for better or worse, now possesses a lineup that includes no primetime sports, having passed on expensive deals in recent years for the NFL, NBA and Major League Baseball.

As long as it has the entertainment series to lead it to victory, the Peacock will grin and bear it when the World Series and Super Bowl boost their rivals’ ratings. It doesn’t need red ink splashed on its ledgers.