If i had a big list or directory of a lot of well known books and how many times s, q, d and r appears in them then sure I would be able to make a very good estimate on how many there are from just looking at the cover of the book, with a slight variance being in the editing that version may have. Almost like how a specific type of food will likely have a certain amount of protein fibre etc, with slight variations based on how the cook prepared the food.