CBS Media Ventures's Jeopardy! has had a string of guest hosts this year since the death of Alex Trebek in November.

The show’s ratings started out on top at 6.2 when Ken Jennings began his six-week guest hosting stint in the week ended Jan. 17. But since Jennings’ start the long-running game show has had a bumpy ride, bottoming out at a 4.4 with LeVar Burton at the podium in the week ended Aug. 1. Burton's stint, though, was heavily impacted by the Tokyo Olympics, which pounded most syndies in the frame.

Jeopardy! has since rebounded: first with CNBC's David Faber earning a 4.5 in the week ended Aug. 8, and then second with Fox Sports' Joe Buck nabbing a 5.2 in the week ended Aug. 15. Buck's rating marked a 13-week high for the game show and a 16% jump over the previous week.

Before Burton and Faber, the game show's lowest rating came in at a 4.7 with Savannah Guthrie, Dr. Sanjay Gupta, and Robin Roberts each earning that number during their respective turns at the podium.

Find out how the guest hosts (so far) stack up below. The most recent ratings are for the week ended Aug. 15 and are based on live plus same day national household ratings from Nielsen Media Research. It's also important to note that ratings are affected by more than the guest host. Preemptions, the Tokyo Olympics, and the slow summer season, for example, all have an impact.

Also Read: New 'Jeopardy!' Host Mike Richards Steps Down After Just 9 Days

Jeopardy! is adding TV doctors Mehmet Oz and Sanjay Gupta and TV journalists CNN’s Anderson Cooper and NBC’s Savannah Guthrie to its roster of guest hosts, Executive Producer Mike Richards said Tuesday. 

As a part of each celebrity’s appearances a donation will be made to the charity of their choice by the Sony Pictures Television-produced game show that will match the cumulative winnings of the contests that compete during the weeks they guest host.

“We look forward to each guest host bringing their unique abilities to the show and to our contestants winning a lot of money that we can match for charity,” Richards said. 

Also Read: Syndication Ratings: 'Jeopardy!' Stays on Top with Ken Jennings at the Wheel

The first two weeks of Jeopardy! without originating host Alex Trebek, who died Nov. 8 of pancreatic cancer, were hosted by Greatest (Player) of All Time and consulting producer Ken Jennings, with both weeks with Jennings at the podium leading Jeopardy! to the top of syndication's household ratings chart.

Richards is currently doing hosting duties. Next up to bat are Katie Couric, Aaron Rodgers, Bill Whitaker and Mayim Bialik 

Also Read: Jeopardy! Welcomes Katie Couric, Aaron Rodgers, Bill Whitaker, Mayim Bialik as Guest Hosts

Oz hosts Sony Pictures Television’s The Dr. Oz Show and is an attending physician at NY Presbyterian-Columbia Medical Center where he still performs heart surgery. He authors a syndicated newspaper column in 175 markets internationally and has written eight New York Times best-selling books, including his most recent, Food Can Fix It.

CNN anchor Cooper is a frequent competitor in Jeopardy!’s Power Players Tournament. Besides anchoring Anderson Cooper 360 on CNN and Anderson Cooper Full Circle on CNN’s digital properties, he is a regular correspondent for CBS’ Sunday night news magazine 60 Minutes and a New York Times best-selling author.

Also Read: Remembering 'Jeopardy!' Host Alex Trebek

Guthrie co-anchors NBC’s Today and also serves as NBC News’ chief legal correspondent. She’s also a New York Times best-selling author for her book Princesses Wear Pants and the sequel Princesses Save the World.

Gupta is CNN’s chief medical correspondent as well as an associate professor of neurosurgery at Emory University and the associate chief of neurosurgery at Grady Memorial Hospital in Atlanta. Gupta also contributes to 60 Minutes and serves as an executive producer for HBO’s documentary unit. His fourth book, Keep Sharp: Build a Better Brain at Any Age, is a New York Times best-seller.

Additional guest hosts and the charities for which they are hosting will be announced later.