As I interpret it, OTA total is equal to 100 minus cable minus ADS If my assumption is true, then OTA accounts for just under 10% (ie homes that are only OTA, obviously there are homes with multiple sources such as satellite and OTA, etc.)
Besides I like to play, my practical side of being on DirecTV and OTA is DirecTV puts me in the Orlando DMA. But their towers are 82 miles away. So my antennas are pointed at the Gainesville UHF and Jacksonville VHF. This gives me more than one DMA between my sources.