Comic Con and other fan conventions are a popular gathering place for all fandoms. It is a great place for fans to interact with other fans and learn more about their beloved book, show, film or what have you.
Eventbrite did a study in 2014 about the demographics of conventions, which also equates to the demographics of fandoms. below is an infographic of the data.
If you want more information about the study that gathered this data, you can go here.