Display two graphics with two different date

Hello,

I have a little question. I want to display two graphics, the first one with a date I choice ( for exemple 13/11/2016) and the second with the same data but 1 year before so 13/11/2015 in this case.

I have no trouble to display the first one, but i don't find a solution to display the second graphics with -1 year.

Have a nice day.