From: https://www.stlouisfed.org/open-vault/2018/june/fascinating-facts-cellphone-smartphone-usage
The latter half of 2016 was the first time that a majority of American homes had wireless telephone service but no landline. This was noted in the April issue of Page One Economics by Jeannette Bennett, a senior economic education specialist with the St. Louis Fed’s Memphis Branch.
That finding comes from the Centers for Disease Control and Prevention’s National Center for Health Statistics, which has been releasing briefs on wireless substitution trends in America since late 2006. The center’s July-December 2016 National Health Interview Survey (PDF)revealed that, for the first time, more than half of American homes did not have a landline, but did have at least one wireless telephone. This was a turning point in the long-running survey.