1 in 8 U.S. households now wireless only
http://www.cdc.gov/nchs/data/nhis/earlyrelease/wireless200705.pdf
Preliminary results from the July-December 2006 National Health
Interview Survey (NHIS) indicate that the number of households with
only wireless telephones continues to increase. During the last 6
months of 2006, more than 3 out of every 20 American homes (15.8%)
did not have a landline telephone. Of those homes without a landline
telephone, most had at least one working wireless telephone.
Preliminary results from NHIS suggest that more than one out of every
eight American homes (at least 12.8%) had only wireless telephones
during the second half of 2006. These are the most up-to-date
estimates available from the federal government concerning the size
of this population.