Table: tv_episode_data_74
Columns: series
season
title
directed_by
written_by
original_air_date
production_code
u_s_viewers_millions

Question: How many original airdates did season 20 have?
SQL: SELECT COUNT("original_air_date") FROM tv_episode_data_74 WHERE "season" = 20

Question: Who directed the episode that was watched by 6.62 million U.S. viewers?
SQL: SELECT "directed_by" FROM tv_episode_data_74 WHERE "u_s_viewers_millions" = '6.62'

Question: What is the production code for the episode with 8.56 million U.S. viewers?
SQL: SELECT "production_code" FROM tv_episode_data_74 WHERE "u_s_viewers_millions" = '8.56'

Question: What is the title of the episode that had 9.76 million U.S. viewers?
SQL: SELECT "title" FROM tv_episode_data_74 WHERE "u_s_viewers_millions" = '9.76'