CREATE TABLE table_2639433_4 (market_share__target_group_14_49_ VARCHAR, viewers__in_millions_target_group_14_49_ VARCHAR)
How many times was the viewer target group 0.63?
SELECT COUNT(market_share__target_group_14_49_) FROM table_2639433_4 WHERE viewers__in_millions_target_group_14_49_ = "0.63"