How to make a dynamic formula to distribute a pre-set number of customers evenly throughou

I'm working on a model to forecast a company's cash flows. One of the features I need the model to have is a changeable number of customers (i.e. 25 customers) and I want Excel to take that number and relatively evenly distribute it throughout 12 months in the year. 25 being an odd number, I'd expect something like 2 customers/month and 3 customers in December.
Any ideas on how to make this dynamic calculation so I can change the number of customers with one click? Obviously, the number of customers need to be integers. Thanks in advance for your help.