By 2011 over 109 million contactless credit and debit cards will be circulating the United States, reports eMarketer. That's no small leap from 27 million in 2006.

The data is derived from "Smart Cards in the US: Contactless Payment Cards," a report by Packaged Facts. Representative Tatjana Meerman explained store owners contributed to the healthy increase in smart card activity, pointing out that the percentage of retailers with contactless payment systems may triple in two years.

The number of contactless transactions is expected to his 2.2 billion by 2011, a leap from about 777 million in 2006.