Table schema:
CREATE TABLE table_name_5 (games INTEGER, debut_year VARCHAR, years_at_club VARCHAR, goals VARCHAR)

Question: Which Games have Years at club of 1977, and Goals of 17, and a Debut year smaller than 1977?
SQL: SELECT AVG(games) FROM table_name_5 WHERE years_at_club = "1977" AND goals = 17 AND debut_year < 1977