Stephen J. Blumberg, Ph.D., and Julian V. Luke – Division of Health Interview Statistics, National Center for Health Statistics: “Preliminary results from the July–December 2013 National Health Interview Survey (NHIS) indicate that the number of American homes with only wireless telephones continues to grow. Two in every five American homes (41.0%) had  only wireless telephones (also known as cellular telephones, cell phones, or mobile phones) during the second half of 2013—an increase of 1.6 percentage points since the first half of 2013 and 2.8 percentage points since the second half of 2012. However, these increases are smaller than those observed in previous years. This report presents the most up-to-date estimates available from the federal government concerning the size and characteristics of these populations.”