The Hollywood Reporter takes a look at the economic engine that’s been created by vampire franchises, from the cult hit "True Blood" on HBO to books such as Justin Cronin’s "The Passage" and films based on books such as the "Twilight" movies. 

The power of the undead may be summed up in one number: $7 billion, the story says. That’s the amount brought to the Hollywood economy by the bloodsuckers, the article adds. While it’s harder to estimate the amount of money that TV shows bring in compared with movies, the article pegs "Vampire Diaries" as likely to generate $100 million to $125 million and "True Blood" as likely to ring up $50 million to $75 million from domestic and international licensing agreements, assuming the shows stay on air for five years.

And DVD sales will add to that, the story says. With the first season of "Vampire Diaries" going on sale next week, and "True Blood" DVDs selling briskly, the two shows could bring in $200 million for the home video market, the article says.