49ers
As of the 2013 season, the college football team that has the best winning percentage in Division 1 is Old Dominion with a winning percentage of .767. Old Dominion has only played 60 games in Division 1 though. Notre Dame is 2nd with a percentage of .733 Michigan is 3rd with a percentage of .732
Tampa bay rays
Assuming that the 2 represents ties, the winning percentage is .619 Assuming that the 7 represents ties, the winning percentage is .738
The 95-96 Chicago Bulls. They won 87 of their 100 games ( including playoffs). This team holds the NBA record for best winning percentage at .878.
I am adding to the answer because the information supplied by the responder has some noteworthy information on the NY Yankees. That answer can be seen in the last two paragraphs. The best New York Yankee lifetime winning percentage by a starting picther is held by Lefty Gomez. He pitched in the 1930's and had a winning percentage of .839. Whitey Ford had a career .690 win percentage for a career, one of the best for any team. Ron Guidry's .893 win percentage in 1978 is also one of the best for any starting pitcher on any team.
NY Mets
New york yankees
alabama, lsu
As of the 2013 season, the college football team that has the best winning percentage in Division 1 is Old Dominion with a winning percentage of .767. Old Dominion has only played 60 games in Division 1 though. Notre Dame is 2nd with a percentage of .733 Michigan is 3rd with a percentage of .732
Through the 2010 season, it's the Chicago Bears. They have a record of 704-512-42 for a winning percentage of .579.
Manchester United
Pittsburgh Steelers
Tampa bay rays
New England Patriots
Through the 2007 season, the American League team with the most wins in a regular season was the 2001 Seattle Mariners with 116. The American League team with the best winning percentage in a regular season is the 1954 Cleveland Indians who went 111-43 for a winning percentage of .721. Seattle's record in 2001 was 116-46 for a winning percentage of .716.
According to the Pro Football Hall of Fame, as of the start of the 2007 season the team with the best all time regular season winning percentage was the Miami Dolphins whose all time regular season record was 368-252-4 for a winning percentage of .593. Second was the Chicago Bears with an all time regular season record of 670-482-42 for a winning percentage of .579.
The Ohio State University, THen Oklahoma