Write SQL query to solve given problem: What is the percentage of the tweets from California are positive?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT SUM(CASE WHEN T1.Sentiment > 0 THEN 1.0 ELSE 0 END) / COUNT(T1.TweetID) AS percentage FROM twitter AS T1 INNER JOIN location AS T2 ON T2.LocationID = T1.LocationID WHERE State = 'California'