Different people in the US have different experiences. Why is some random anecdote (assuming it's not made up) good enough to define xxx million people? I don't

Different people in the US have different experiences. Why is some random anecdote (assuming it's not made up) good enough to define xxx million people? I don't get 2-5 calls per day. My experience is more like what you describe with the UK. But that could be affected by my being on the do not call list on one hand, and on the other, occasionally answering a telemarketer by accident when I'm waiting for another call.