According to this random quora link: https://www.quora.com/How-much-does-McDonalds-make-in-a-day the average McDonald's unit in the USA has $2,670,320 in annual sales. 25% - 40% profit margin sounds really high for a restaurant, but I don't know enough about the industry to dispute it. Are you sure those numbers were presented as averages and not the high end of what you could make? Or does the typical owner have multiple locations?
Very possible I skimmed and may have read it incorrectly, accounting is not my thing. As I have now reached the maximum amount of effort I'm willing to put into a forum comment, I'm not going to dig any further. But if you can tease out better information, I'd be curious to know.
From the document... Across ~12,000 locations they put the majority of restaurants in a range but they do have the numbers pretty well crunched.
Average profit margin 26-28%
Average gross sales 2.2 - 2.6M
Average operating income before rent/tax: 570k - 716k
"The rent paid to McDonald’s will vary based upon sales and McDonald’s investment in land, site improvements, and building costs."
It looks like that rent paid to McD's home planet is somewhere in the neighborhood of 10% of that investment (yearly? I guess?) but it seems to average about 100k-150k.
My source is from the McDonald’s franchise disclosure documents. The money blog mentioned in sibling comments claim it’s less.