Calculate current per hour rate each time a button is clicked

I'm trying to create an area on my userform that shows how many times a button is clicked per hour. I would like the number to update on my userform every time the button is clicked. I have working code to count and display the number of times a button is clicked, but how would I go about calculating the current hourly rate each time the button is clicked? I'm guessing it would need to be some kind of estimate based upon a table I would need to create. I'm currently playing around with some code that exports the current time to a sheet each time the button is clicked. I also have a login time that records the beginning of the session on a sheet. I was thinking I could somehow manipulate these times via formulas in the spreadsheet, but I'm not sure where to begin. Any suggestions?