CREATE TABLE table_name_56 (most_recent VARCHAR(255), height__m_ VARCHAR(255), first_time_as_hc_climb VARCHAR(255))
What was the most recent year a height of 2770 m and a HC climb before 1992 was climbed?
    
SQL: SELECT COUNT(most_recent) FROM table_name_56 WHERE height__m_ = "2770" AND first_time_as_hc_climb < 1992