Two bar graphs, Graph 1 and Graph 2, plot the exact same underlying quarterly sales data for a company. Graph 1's vertical axis starts at 0, with each unit representing 10 units of sales. Graph 2's vertical axis starts at 50, with each unit representing 2 units of sales, making Graph 2's bars appear far more dramatically different in height from each other than Graph 1's bars. Which of the following is actually the same between the two graphs?