YES/NO questions on a map visualisation

Hi, 

I have a question in an app that is a yes/no question, when visualizing this as a map in powerBi (using postcodes), the tooltips shows them as a count, showing many times the question has been answered for each postcode, rather than a yes/no. How do I turn this count function off, so that when I hover over a data bubble on the map, it can show whether the anser is yes or no.