The related questions are:

1. What is the average percentage of businesses in the United States
that pay to run a printed "Yellow Page" ad? In other words, of all the
businesses in the US, what percentage of them run printed ads in the
"Yellow Pages"?

2. What is the average number of orinted "Yellow Page" ads per capita?
For example, in a county with a population of 200,000 citizens, what
how many Yellow Page ads are in their book?

3. What is the average cost of a "Yellow Page" ad in the United
States? I realize there are many variables here, such as region, size
of ad, etc. But I just need a ballpark average.