Unsure. I know we haven't had cable/sat for six years now and haven't looked back. Sure, I miss the history channel from time to time, but the only time we watch TV is for superbowl, etc. The rest of the time we stream through netflix or amazon, so we went from $150 or so a month to 7.00 for amazon prime and 8.00 netflix.
I don't think we're alone, which gets to your point about how many people are out there. How would you even begin to measure that number?