Context: CREATE TABLE table_name_18 (loses INTEGER, wins VARCHAR, draws VARCHAR, year VARCHAR, competition VARCHAR)
Question: What sum of Losses has Year greater than 1972, and Competition of nswrfl, and Draws 0, and Wins 16?
Answer: SELECT SUM(loses) FROM table_name_18 WHERE year > 1972 AND competition = "nswrfl" AND draws = 0 AND wins = 16