The proportion of cell-only households in the US rose to 22.7% in the first half of 2009, according to the latest figures. A further 14.7% of homes had a landline but rarely if ever used it, meaning that about 85 million American adults are now cell-only or ‘cell-mostly’.

Wayne Russom, ORC senior vice president and director of Caravan omnibus services, said: “In the past few years, the cell phone has become an increasingly important part of the American way of life. For some, it has become the primary and, in several cases, the only source of telephone contact. This is particularly true of young adults in the 18-35 age bracket.

“With the introduction of the Caravan enhanced sample methodology, clients are able to examine this important and growing segment of our population.”

The survey is conducted twice-weekly and the sample also includes 1,000 landline households, recruited via random-digit dialling (RDD). Russom said that RDD would remain a viable way of polling the US public, but “eventually any sample will need to incorporate cell phone interviewing to be truly projectable”.