Creating a level per show

I would like to create a rating level from 1-5 to see how well my shows have done. To see that I would take the gross sales of the show, and negative the gross expanses. So, if like, the shows sales are $1000, and the expenses are $1, then that would be a level 5 show. Now, if the shows sales are $1, and the expanses are $100, then it would be a level 1 show. How would I do/create that? I would just need a query, with the percentages of the levels that I could change. So if total percentages of the show total after negativing the gross expenses from the gross sales is 500% more, then that show was good. Thanks! :)

Creating a level per show