This is a graph, per the CDC, of the percentage of “cellphone-only” adults in the United States. The fraction, as of the second half of 2009, was 23 percent of all U.S. adults, or 25 percent of all U.S. households. These adults — about a quarter of the population — are simply ignored by many pollsters.
This is not a new problem — in fact, it’s one we’ve written about on several occasions. But it’s continuing to get worse. The percentage of people who have replaced their landlines with cellphones has climbed at a remarkably steady rate. (There may have been an especially large leap from the second half of 2008 to the first half of 2009, when the recession was at its worst and many people were looking for ways to trim household costs.)
» via FiveThirtyEight