Looking for Simple Rating Plugin/System

I am looking for what I feel is a very simple plugin. A Rating plugin that will allow me to put a 5 star rating anywhere on my site that total to one aggregate rating.

Then I want to be able to put the total rating wherever I would like in schema.org markup.

A site wide rating of a business website. So customer can come and rate, and *hopefully* the aggregate rating will show up as a rich snippet.

Any suggestions? Everything that I can find seems to just be for posts.