Back around 2003 in the United States, the Centers for Disease Control (of all agencies) started tracking statistics about cell phones and landline use in the United States. They did so to ensure that their health interview statistics accounted for a representative sample of all people. Since then, they have ended up being the federal agency that tracks phone use across the United States.
In 2017, the CDC reported that the number of people that have a cellphone only surpassed 50%, with only 6.5% of people reporting that they had a landline phone, with no cell phone. The rest of their statistics are all people with both a landline and a cell phone. It is not, however, an equal split. A greater portion of adults living in poverty and near poverty were relying solely on cell phone service, the CDC said. Among higher income adults, only 49% were mobile-only.
The cell phone vs landline separation doesn’t exist only in the United States. In 2014, the Pew Research Center looked at the penetration of cell phones and landlines in South Africa, Nigeria, Senegal, Ghana, Kenya, Tanzania, and Uganda. Between 65 percent and 89 percent of adults in those African countries all have a cell phone.
However, unlike the United States, where landline phones are more common, only 2% of the African continent residents surveyed had access to a wired telephone.
Which, from an infrastructure standpoint makes sense. In fact, in 2012, more people in Africa had access to cellphones than had access to electricity. Even when you do have access to electricity and landlines, however, more and more people are choosing to go cell-only.