The US Center for Disease Control (CDC) is tracking the number of US households that are "wireless only" or primarily wireless. Wireless only means there is no landline in the house; primarily wireless means that people receive "all or almost all calls on wireless telephones despite also having a landline telephone."
My wife and I, and others we know, fall into that second category. We have a landline but rarely use it. It's a number we give out for "official purposes" and it acts as a telemarketing "spam catcher." The majority of people who call that number get voice mail.
The last time I wrote about this data, in June, the CDC reported that just under 30% (29.7%) of American households were wireless only. Beyond this, 15.7% of US homes received all or almost all calls on wireless telephones." In total, 45.4% of US homes were either mostly mobile or wireless only. The CDC findings were based on polling data from the first half of 2011.
Earlier this week I checked back to see if the numbers had changed at all since June. They have; they've continued to grow.
According to CDC data collected between July and December 2011, 34% of American homes are now "wireless only." In addition 16% are mostly mobile, receiving "all or almost all calls on wireless telephones despite also having a landline telephone." This means that a total of half of all US households now rely primarily or exclusively on mobile phones.
The populations, according to the CDC, mostly likely to be mobile only are the following: younger people under 34, adults living alone, those without higher education and less affluent or poor families. Those more likely to be mostly mobile are: affluent adults, parents and adults with college degrees.
Because these data lag about six months we can estimate that the current combined figure is probably closer to 55% of US homes being mobile only or mobile first.