@MLBReplays is the official MLB instant replay twitter account, it tweets the details of every challenged call.
This site automatically parses @MLBReplays' tweets.

TeamOverturned CallsUpheld CallsChallenge Effectiveness
Atlanta Braves124.750
Miami Marlins145.737
Umpires Crew3285.726
Kansas City Royals168.667
New York Yankees137.650
Milwaukee Brewers95.643
San Francisco Giants1710.630
Washington Nationals138.619
Detroit Tigers149.609
Texas Rangers107.588
Los Angeles Dodgers1310.565
Anaheim Angels108.556
Baltimore Orioles108.556
Houston Astros108.556
Boston Red Sox119.550
Cleveland Indians119.550
Pittsburgh Pirates1210.545
San Diego Padres87.533
Chicago White Sox98.529
Arizona Diamondbacks109.526
Minnesota Twins1211.522
Seattle Mariners99.500
New York Mets910.474
Oakland Athletics89.471
Chicago Cubs1417.452
Philadelphia Phillies811.421
Colorado Rockies1014.417
Tampa Bay Rays1120.355
Toronto Blue Jays921.300
Cincinnati Reds39.250
St. Louis Cardinals312.200