Members age statistics and show age for all

[MonkYZ]

Hello everyone. I just found a sponsor for one of my websites, and he requires to know what my member average age is. I couldn't find any way to create statistics for this, so i was wondering if there is some plugin or an option to do that.

Also, in my members list i can't see their ages (even as admin) as most of them choosed not to show their ages. Is there a way to force the age to be shown to all (or at least to admin/moderator usergroup) ?

Thank you in advance !