Approximately 16.1 percent of US adults (36 million) live in wireless-only households, while 17 percent (12 million) children live in households with nothing but a cell phone, according to the National Center for Health Statistics (NCHS). Just a year before, it was one in eight. And it's nearly three times as many as in 2005, according to a survey released by the U.S. Centers for Disease Control and Prevention.

The figures come from national in-person interviews of approximately 30,000 households per year with at least one adult or child. According to their latest data, 17.5% of households are now wireless only, up from 13.6% one year earlier. Interestingly, the government data indicates that "wireless-only households are more likely to contain binge drinkers and smokers, compared with those having landline phones." About 2.5% of U.S. households have no phone at all. The figures, covering the first half of 2008, underscore how consumers have been steadily abandoning traditional landline phones in favor of cells.

"There's clearly a reason to give up a landline phone if budgets are tight," Stephen Blumberg, senior scientist at the federal Centers for Disease Control and Prevention and an author of the report said in an interview. "Given the current economic environment, I'd not be surprised to see more and more people give up their landline phones for economic reasons."

The in-person survey of 30,000 people found that another 13 percent of people have a landline but rarely use it, which, as CBS’s Katie Couric points out; means that nearly one-third of Americans get most of their calls on a cell phone.