How many percent of countries in North America use English?
percentage = MULTIPLY(DIVIDE(COUNT(Language = 'English' WHERE Continent = 'North America'), COUNT(Language WHERE Continent = 'North America')), 1.0); North America refers to Continent = 'North America'; use English refers to Language = 'English';
SELECT CAST(SUM(IIF(T2.Language = 'English', 1, 0)) AS REAL) * 100 / COUNT(T1.Code) FROM Country AS T1 INNER JOIN CountryLanguage AS T2 ON T1.Code = T2.CountryCode