Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, contentious.com, explores how people communicate in the online age.
(CNN) -- If you needed any evidence that landlines are waning, here it is: According to new research from the U.S. Centers for Disease Control and Prevention, nearly one-fourth of all U.S. households use only wireless phones.
The states with the highest proportion of wireless-only households are Arkansas and Mississippi -- neither of which is known as a high-tech hub -- at just over 35% each. Both saw growth of about 15% in this sector from January 2007 to June 2010.
The lowest wireless-only rates were found in New Jersey and Rhode Island, both at nearly 13% as of June 2010.
The report offers no explanation for this disparity. However, I'm guessing that U.S. economic conditions have spawned wireless market opportunities in unexpected places.
For instance, mobile phone service is increasingly viewed as more of a daily necessity than landline service, especially among people facing financial challenges. So Arkansas and Mississippi might be topping the wireless-only list because those states were hit especially hard by the recent recession.
Not coincidentally, discount and regional wireless carriers have been expanding their networks significantly outside major metro areas, offering the flat-rate monthly no-contract plans that are especially attractive to people on limited budgets.
Of course, that's just a guess. The "why" behind this transition -- and especially the wide regional variation in household telephone preferences -- is worth further research.
Here's why the CDC is presenting these telecom statistics: On an ongoing basis, the CDC conducts the National Health Interview Survey, primarily via telephone interviews. Since it's crucial for the CDC to reach a representative sample of the full U.S. population, the NHIS has become the most widely cited source for data on the ownership and use of U.S. phone lines.
The latest report, published Wednesday as part of the NHIS Early Release Program, presents national and regional estimates. The report features tables showing wireless household rates from January 2007 through June 2010, both for states and for several counties (mostly around major metro areas) within most states.
According to the CDC, as of June 2010 "more than one in four American households (26.6%) had only wireless telephones -- an eightfold increase over just six years. The prevalence of wireless-only households now markedly exceeds the prevalence of households with only landline telephones (12.9%), and this difference is expected to grow."
I hope the CDC -- or somebody -- republishes these rates in a searchable database format, because this data offers intriguing context for how local communication preferences shift.
For instance, in Alameda County, California, in 2007 only 9.6% of households were wireless-only. But by June 2010, this nearly doubled to 17.4%.
Also, in 2007 in the city and county of Denver, Colorado, 26.1% of households were wireless-only. By June 2010, 33.6% were -- a 7.5% increase. But throughout the rest of the state of Colorado, wireless-only households grew from 16.8% in 2007 to 28.4% by June 2010 -- an 11.6% increase.
The CDC report also compared rates among states and some counties or other sub-state regions for these categories: wireless-only, wireless-mostly, dual-use, landline-mostly, landline-only, and no phone service.
Here are some interesting numbers from that table:
• South Dakota has the highest rate by far (50.8%) of landline-only households.
• Minnesota's Twin Cities area had the lowest reliable estimate of landline-only homes: 5.7%.
• Davidson County, Tennessee, which includes Nashville, had an even higher rate (37.5%) of wireless-only households than Arkansas and Mississippi.
• Central and northern New Mexico counties had the highest collective rate of households with no phone service: 4.5%.
• Santa Clara County, California, has the lowest U.S. rate of landline-only households: 0.6%
The opinions expressed in this commentary are solely those of Amy Gahran.