Table schema:
CREATE TABLE table_name_54 (_number_of_prefectural_votes VARCHAR, _number_of_seats_won VARCHAR, leader VARCHAR)

Question: What is the total number of # Of Prefectural Votes, when # Of Seats Won is greater than 69, and when Leader is Yasuhiro Nakasone?
SQL: SELECT COUNT(_number_of_prefectural_votes) FROM table_name_54 WHERE _number_of_seats_won > 69 AND leader = "yasuhiro nakasone"