According to a recent study by Pew Internet, 46 percent of American adults are now smartphone owners. That is 53 percent of overall adult cellphone owners in the US, while the others own the good old cellphone.
Conducted between April and May of 2011, the study also analyzes the smartphone growth based on different demographic groups and income, as well as education. It reveals that many smartphone adopters are young adults (between 18 and 24) with some college education.
Head over to Pew Internet to read more about this study.