62% of iPhone 4S owners use Siri several times a week

"Parks Associates' consumer study of Siri users revealed several interesting pieces of data. Here are some additional points we found intriguing:
Of iPhone 4s users, 62% use Siri for some function at least several times a week, including 35% of respondents who report daily use.  The least used functions are playing a video, scheduling a meeting, or playing music."

Source:  Blog post by Parks Associates, 28th March 2012