How do you get the # of issues "in progress" from a given version using API?

[Peter Johnson]

My goal is to be able to recreate this chart on an external dashboard system:

Have read through the latest API docs here, and tested it out on my own. 

GET /rest/api/2/version/{id}/unresolvedIssueCount is the closest endpoint that returns a value for issuesUnresolvedCount and total issuesCount, (which I can use to deduce the doneIssueCount) but I don't get a value for issuesInProgressCount anywhere. I don't see any of the version endpoints that returns those values.

So my question is: 

Do I simply have to write a GET /issues query to see the count? or am I missing something. 

[Christoph Thomas (Karlsruhe, Germany, AUG Leader)]

How about executing a JIRA search or multiple JIRA searches using JQL as you would do in JIRA? Not sure what's the name of the function (GET /issues as you suggested above) but there should be some API function like selectIssues combined with the right JQL returning the desired result for you which you can then count.