Table schema:
CREATE TABLE table_name_1 (population__region_total_ INTEGER, year VARCHAR, population__mareeba_ VARCHAR)

Question: What was the sum total of the region after 1976 when Mareeba had population was more than 18,212?
SQL: SELECT SUM(population__region_total_) FROM table_name_1 WHERE year > 1976 AND population__mareeba_ > 18 OFFSET 212