But for a "fair" comparison you would also have to adjust based on the cost of attending a movie compared to average income (it's increased disproportionally, even over the past 20 years), and take into account the other forms of entertainment that are available today compared to back then. Heck, forget video games, Cable BluRay, DVDs - even the choice of movies available today is likely to be far larger than back in 1939 :)