This is an accepted solution.
You can use the Sales over Time report as your base, and then edit the columns to tailor the report to your liking. In your case, you would want to check off the following columns:
Canceled, Returns, Returned Quantity, and Orders.
From there, you will have a report that looks like the following:
At the top of the report page, you can also set the date range of orders to see the number of returns and exchanges over a set period of time. I hope this helps!
If there is anything else I can help you with, please let me know.