I don't seem to getting the output from a data service gzip'd

 this could be a MVC post, but I think better here.
I've got a simple controller that just returns json data.  I know that my production web server (iis7) is really gzipping things because I can see the results in the size of the javascript coming down.
However, on this ActionResult return, I know the results are not gzipped and that would help a large amount.  I'm attaching the fiddler screen shot.
Any suggestions to encourage iis to gzip this?  Is it possible?

 
 
 
public ActionResult GetLoadSegme ...