The majority of people say they use numbers, letters, and symbols in passwords
Study: ESET & Harris Interactive Password Poll
Date: October 22 2012
Respondents were asked if the following statement applied to them: "When creating any personal password (e.g., online accounts, computer networks, device access codes), I use a combination of numbers, letters and symbols."
My suspicion is that poll respondents must have toiled away searching the dark corners of their minds for a faint memory of that one time they accidentally typed a symbol into a password and used it. The overwhelming evidence provided by publicly leaked passwords does not support this as a common practice.