Hours of Operation for the Chicago Board of Trade Building Observation Deck in 1930 (price)

[Nyc1664]

From what I understand, the ticket price for the Chicago Board of Trade Building observation deck was 50 cents for adults and 30 cents for children when the deck first opened in 1930. I also found that the price was 30 cents for all in 1947 and 50 cents for adults and 25 cents for children in 1970. The hours of operation were 9 am to 9 pm 7 days a week in 1947, but in 1970, they were 9 am to 5 pm Monday-Friday. The deck was finally closed to the public in 1971 due to the competition from the higher observation decks at the Prudential Building that was opened in 1955 and the John Hancock Center that was opened in 1969. However, I have not been able to find what the hours of operation for the Board of Trade observation deck in 1930, but found that they were open to the public daily. So, does anyone here know what the hours of operation were in 1930 and also when the hours of operation changed from being open 7 days a week with night hours to weekday business hours only. Also, why did the hours of operation change from 7 days a week with night hours to weekday business hours only, presumably some point after the Prudential Building observation deck opened to the public in 1955.