CREATE TABLE table_name_86 (points INTEGER, goals_for VARCHAR(255), goal_difference VARCHAR(255), club VARCHAR(255))
what is the average points when the goal difference is less than 17, the club is getafe cf and the goals for is more than 30?
    
SQL: SELECT AVG(points) FROM table_name_86 WHERE goal_difference < 17 AND club = "getafe cf" AND goals_for > 30