Among all the root beers sold in 2014, what is the percentage of the root beers produced by the brewery AJ Stephans Beverages?
sold in 2014 refers to SUBSTR(TransactionDate, 1, 4) = '2014'; percentage = DIVIDE(MULTIPLY(SUM(BreweryName = 'AJ Stephans Beverages'), 1.0), COUNT(RootBeerID)) WHERE SUBSTR(TransactionDate, 1, 4) = '2014'; AJ Stephans Beverages refers to BreweryName = 'AJ Stephans Beverages';
SELECT CAST(COUNT(CASE WHEN T3.BreweryName = 'AJ Stephans Beverages' THEN 1 ELSE NULL END) AS REAL) * 100 / COUNT(T1.BrandID) FROM rootbeer AS T1 INNER JOIN `transaction` AS T2 ON T1.RootBeerID = T2.RootBeerID INNER JOIN rootbeerbrand AS T3 ON T1.BrandID = T3.BrandID WHERE T2.TransactionDate LIKE '2014%'