The number of bills accumulates, because people do not want to take the marked up bills as change. So after going through a bankers pack of one hundred dollar bills, perhaps five of them are marked up and get stuck in the till. A week later, and other $100 pack, there are ten unwanted bills… repeat ad nauseum.
I work in a hotel. There is only one till. Due to requiring a credit card to rent a room 99% of our use of one dollar bills is to make change for customers using the vending machines. They accumulate rapidly because the only other way to get rid of them is to take them to a bank. So yes, once they get in the till, they are still there pretty much every day.
