What is the percentage of rated movies were released in year 2021?
percentage = DIVIDE(SUM(movie_release_year = 2021), COUNT(rating_id)) as percent; movies released in year 2021 refers to movie_release_year = 2021;
SELECT CAST(SUM(CASE WHEN T1.movie_release_year = 2021 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM movies AS T1 INNER JOIN ratings AS T2 ON T1.movie_id = T2.movie_id