Most Americans Live in Wireless-Only Households

From CDC's National Center for Health Statistics:

Since 2007, the National Health Interview Survey (NHIS) Early Release Program has regularly released preliminary estimates of the percentages of adults and children living in homes with only wireless telephones (also known as cellular telephones, cell phones, or mobile phones). These estimates are the most upto-date estimates available from the
federal government concerning the size and characteristics of this population.

In January 2019, the NHIS launched a redesigned questionnaire. Among other changes, it is now possible to estimate the percentage of adults who live in wireless-ly households and have their own wireless telephone (wireless-only adults).

Estimates in this report are based on the first six months of 2019. During this time period, 59.2% of adults and 70.5% of children lived in wireless-only households.
In comparison, a slightly smaller percentage of adults were wireless-only adults (58.4%). Four in five adults aged 25–29 (80.2%) and aged 30-34 (78.3%), and three in four adults renting their homes (75.1%), were wireless-only adults.

...
Many health surveys, political polls, and other types of research are conducted using random-digit-dial (RDD) telephone surveys. Most survey research organizations include wireless telephone numbers when conducting RDD surveys. If they did not, the exclusion of\ households with only wireless telephones (along with the small proportion of households that have no telephone service) could bias results. This bias— known as coverage bias—could exist if there are differences between persons with and without landline telephones for the substantive variables of interest.