What is the average winning rate of the Montreal Canadiens in the Stanley Cup finals?
DIVIDE(SUM(DIVIDE(W,G), COUNT(oppID);
SELECT SUM(T2.W / T2.G) / SUM(T2.G + T2.W) FROM Teams AS T1 INNER JOIN TeamsSC AS T2 ON T1.tmID = T2.tmID AND T1.year = T2.year WHERE T1.name = 'Montreal Canadiens'