Write SQL query to solve given problem: Calculate the percentage of sales done at Sac State American River Courtyard.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(COUNT(CASE WHEN T2.LocationName = 'Sac State American River Courtyard' THEN 1 ELSE NULL END) AS REAL) * 100 / COUNT(T1.TransactionID) FROM `transaction` AS T1 INNER JOIN location AS T2 ON T1.LocationID = T2.LocationID