You will probably want one table for stores it will have the store number that it is indexed on and any other relevant data for the store name address etc.
You will have one table for employees. Including an employee name or number that it will be indexed on and any other relevant information for the employee home address salary whatever is important for any jobs you will be using the data base for. Maybe very few if its only for the classes taken. But it will need to include a field for the store number where they work.
Then you have the course data. You may or may not want to have a heading table with a course number that it will be indexed on and a course description etc
then you will have the actual data table that includes fields for the course number and the employee number ( just for convenience another field called started with a 1 in it )and a field for whether it was completed or not with a 1 if it was completed as the data
To create the report
you link the course data table to the course header table by the course number ( optional )
you link the course data table to the employee table by the employee number in both
you link the employee table to the store table by the store number field in both tables
then you create the report
you can easily list out all courses taken all course completed. sort it by store or by employee or even list the stores and employees by course number
for the report that you want you would add the completed field and the taken field and subtotal on it them with a subtotal field for one divided by the other
sorting by store. or employee and store if you so desire.
then if you dont want to see the individual courses you can set that portion of the report not to print. then you only see the percentage by store.