What is the percentage of American coaches among all the coaches who taught the Montreal Canadiens?
American refers to birthCountry = 'USA'; DIVIDE(COUNT(coachID where birthCountry = 'USA', name` = 'Montreal Canadiens'), COUNT(coachID where name` = 'Montreal Canadiens')) as percentage;
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'