Jacker,
I do not care for those population numbers. Based on theaters that I have looked at, that population would generate about $200-250,000 in ticket sales on average. A brand new theater that size could easily run you $1 million not including digital equipment.
I like the 45 mins to competition. Look for populations a min. of 25,000 for a 4 screen and up and I would not even consider building a new theater with fewer than 4 screens.