Write SQL query to solve given problem: Calculate the win rate of the toss-winners in 2012.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN Toss_Winner = Match_Winner THEN 1 ELSE 0 END) AS REAL) / SUM(CASE WHEN Match_Date LIKE '2012%' THEN 1 ELSE 0 END) FROM `Match`