Additional field for Customers in Prestahop

I have a client that is currently running prestashop 1.3. I've upgraded it to prestashop 1.4.1 on a development server and in the process of creating a new theme for it as well. While this redesign and upgrade is taking place we are also looking at adding a custom field during the customer registration process or shopping cart checkout. It would be a drop down field "How did you hear about us?", and a custom textfield to fill in "Other". We'd like the results of this field to be displayed in the back-end of prestashop on the customer details page, and a statistics page with a breakdown of percentage for each answer.