Question: What is the percentage of American coaches among all the coaches who taught the Montreal Canadiens?
SQL: SELECT SUM(CAST(T2.W AS REAL) / 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'