data validation question

Hello,

I'm new to Excel and I've just figured out how to use Data Validation to create these handy dropdown boxes, at any rate here is my question:

Is there a formula that I can use that takes the information from a column (or row) that has data validation boxes w/ either a "yes" or "no" option and have it return the % of "yes" and "no" answers.

I'm not sure if that makes any sense, but...if have a list of 72 items and in columns C1-C72 have the data validation boxes in them, and 40 are selected as "yes" and 32 are selected as "no", is there a formula I can use to have box C73 tell me the % of 'yes" answers and box C74 tell me the % of "no" answers.

Any help would be greatly appreciated.

Kind regards,