Compare values for a category in Google Analytics event tracking

I have event tracking setup on our Where To Buy form where the users enter the zip code they want to search for dealers.

The event value is the zip code entered.

What I would like to see is a graph of entered zip codes but so far I have only been able to see the overall performance of the event category and not the data I was hoping to see.

Is there a way to make the event report display a graph of the values for an event category? Or do I need to change this event tracking to make the zip code the category?