What is an average attendance of a small cafe per day with 5 tables and a maximum capacity of 25 people?

How long is the cafe open each day ? How long do people stay ? Does it serve just drinks and ready-made snacks, or cooked food ? And how do you define "average" in this context ? Do you mean the average for this particular establishment over a week, a month, etc., or the average over several small cafes with 5 tables and 25 capacity ?

There is nowhere near enough data to even begin to guess at a possible answer to this. How is it rude of Chris P to state an obvious fact ? If you ask such a question on a public forum, you have to grow a thicker skin. You are liable to experience much worse than that betimes.

That's impossible to answer.

Did you assume that every café of that size had identical attendance, regardless of location?