Math Challenge Update

It has been brought to my attention that the question was not clear enough. I'm looking to see how many rounds of calls it would take to reach everyone in the United States. In the video the first round would be me calling the two little people. Then they each call two other people. It would continue until all people have been called. So far Lauren answered 157,277,500 calls. Based on how many rounds of calls would have to be made it would be too high. However, if Lauren explains her work and convinces me that she made a plan, worked it out, and found that result, but it's not technically the right answer. How many rounds of calls will it take to reach all USA people if each person calls two people each round?