Change Over Variable Value in Percentage

Hi, I have a cluster column chart of different antigens i.e. BCG, P-1, P-2, P-3, M-1 & M-2. (all of one month). The BCG is 94%, P-1 is 88%, P-2 is 85%, and so on. I want to draw a graph that not only shows a cluster column chart but also the difference between BCG & P-1, P-1&P-2, P-2&P3, and so on. I tried to find the solution but in vain. Is there any way?

PS: I don't want "change over time" because this is of the same month and has different variables. I want differences or changes among the variables.