What were the difference of the CHS team's winning rate between 1946 and 1947 in the post-season series games? Please provide your answer in percentages.
CHS team refers to tmIDWinner = 'CHS'; difference = subtract(divide(count(series_post where year = 1947 and tmIDWinner = 'CHS'), count(series_post where year = 1947)), divide(count(series_post where year = 1946 and tmIDWinner = 'CHS'), count(series_post where year = 1946)))
SELECT CAST(SUM(CASE WHEN year = 1947 AND tmIDWinner = 'CHS' THEN 1 ELSE 0 END) AS REAL) * 100 / SUM(CASE WHEN year = 1947 THEN 1 ELSE 0 END) - CAST(SUM(CASE WHEN year = 1946 AND tmIDWinner = 'CHS' THEN 1 ELSE 0 END) AS REAL) * 100 / SUM(CASE WHEN year = 1946 THEN 1 ELSE 0 END) FROM series_post