About 3% of U. S. homes have NO phone at all.  About 9% have only landlines and about 48% have both.  Younger folks rely more on cellphones – 2/3 of people in late 20s live in households with only cellphones, while 14% of people 65 and old use only cellphones.  Men are more likely than higher-income folks to have only cellphones.  Landlines are usually kept as have a package of Internet and cable TV package or tied to their security system.  This information from the Centers for Disease Control and Prevention who have keep up with this for 10 years.