Question: How many restricted horror movies were released between 1/1/1990 to 12/31/2015?
SQL: SELECT COUNT(movie_title) FROM movies_total_gross WHERE MPAA_rating = 'R' AND genre = 'Horror' AND CAST(SUBSTR(release_date, INSTR(release_date, ', ') + 1) AS int) BETWEEN 1990 AND 2015