Lists?

Hi,
I'm a bit of an excel noob, and have been making a spreadsheet of all the dates and info on pokemon games ( go on, call me sad :P ).
I've been trying to create a drop down list with Yes and No in it, but i would like them to be sort of add-up-able, if that makes sense, I would like to have 2 cells, one that adds up all the Yes's, and one that adds up all the No's, I don't even know if this is possible, but I'm using Excel 2008 for mac.
Thanks
Joe
P.s, if anybody knows of any release dates for Japan, USA or UK/EU , I would really appreciate it.