creating a frequency histogram in VBA

Book1.zipPlease see the attached Excel file. Below the matrix there is a list of cities and their distances. At the bottom of the list is the sum of the total distances. If you highlight two successive cities (for example, cities 5 & 6 or 2&3 or 8 & 9) and press the "swap cities button" the order changes and so does the total distance. I want to create a histogram that keeps track of the number of iterations. That is, the number of iterations on the x axis and the total distance on the y axis. I want the graph to update automatically everytime the "swap cities" button is pressed. Can someone please help me?