Yep, 84%. They have a winning record against every country they have played, and have never lost to Ireland, Scotland and a number of other countries.
In comparison, the Yankees have an overall win percentage of about 57%, the Dolphins and Cowboys (gridiron) around 57%, Manchester United (soccer) 62%, Montreal Candiens (hockey) 61%, L.A. Lakers (basketball) 61%, Australian Cricket 65%, Kentucky (college hoops) 76%, Michigan (college football) 74% and the Brazilian soccer team is somewhere between 70-75% I believe.