I have two sharepoint lists that are updated by an app.
The first sharepoint list called installer is a list of people and contact information for various companies we do business with.

The second list is called tracking. It is used to track progress dates for various installations we have going on at many different locations with different installers.
Here is a snippet from the tracking list. There is more but it's mostly date fields that get filled in as the project progresses and a few other text fields

As you can probably guess the installer information is a dropdown in the app that updates the installer information in the Tracking list.
The installer list has around 25 different entries with 14 different companies. There are multiple installer contacts for some companies.
There may be companies that move off the tracking list for a few months then come back on the tracking list with a new project.
The company information is still in the installer list even if there are no active projects with that particular contact in the tracking list.
What I am trying to do in my app is get a count of jobs from the tracking list for each installer company and put that into a data table I can display in the app rather than exporting the tracking table to excel and filtering manually on different installercontact:company.
I'm looking for something like this:
Company A 12
Company B 2
Company X 5
Company J 14
On the surface it seems like it should be easy but I have been trying different things for a few days and have not been able to come up with a way to do it.
Any thoughts, suggestions, comments are welcome.
Thanks!