
More than 20 million US telephone households (17%) are now “wireless substitutors” - homes without landlines that rely solely on a mobile phone - and one in five households could be wireless-only by year’s end, according to a study by Nielsen Mobile.

As the US economy tightens and consumers seek ways to cut household spending, many are choosing to eliminate their landline phone service, which costs an average of $40/month per landline household, Nielsen said.
Specific stats about cord-cutters, according to the Nielsen Mobile study (pdf):