Usually Christmas is considered the “most wonderful time of the year” but don’t tell that to Discovery Channel.

The cable network begins the 30th edition of its annual “Shark Week” on Sunday, and according to data provided to TheWrap from Standard Media Index, those Great Whites have generated more than $36 million in advertising revenue over the past two years.

Per SMI, last year’s Shark Week brought in $20.2 million in advertising revenue, a jump of 59 percent over Discovery’s average weekly revenue in 2017 of $12.7 million. In 2016, Shark Week earned $16.6 million in revenue, a more modest jump of 37 percent from the 12.1 million in ad revenue that Discovery earned on a weekly basis.

Also Read: 'Shark Tank' Sharks to Actually Swim With Sharks on Shark Week Special

Since SMI only looks at historical data, they did not have a projection for how much Discovery will rake in this year.

Shark Week begins Sunday at 7 p.m. and runs through the following Sunday, July 29. This year’s festivities feature the likes of Shaquille O’Neal, Ronda Rousey, Aaron Rodgers, Rob Gronkowski, Lindsey Vonn, Guy Fieri and Bear Grylls. It will also see the stars of ABC’s “Shark Tank,” including Marc Cuban, swim with actual sharks.

Discovery’s annual shark appreciation has become so popular that other networks have been following suit. Nat Geo Wild has been doing their own version called “SharkFest” since 2012, which kicked off a Megaldon-sized two week programming block this past Sunday. That means these two fishes will go head to head next week.