It can be quite helpful to be able to see how this year's numbers compare to last year's. Start by going to "Graphing", then "Single Stat Graph".
Set the dates for whatever period you need to view, check the "Overlay Prior Year" box, and click "Re-Graph Stat".
That's all there is to it! The red and black line indicates this year's numbers, while the dotted green line indicates last year's numbers.