How many rounds of the monopoly table occur per monopoly match?
According to one source that provides Monopoly statistics, it is about 30 turns per player.

Source:


  Since the average game of Monopoly takes about 30 turns per competitor[...]


Unfortunately they don't provide more detailed analysis showing the numbers used in calculating this average number of turns, but the page does include specific statistics to suggest that this number is more than just a guess.