Line Chart with 3yr average line and current FIN year line


I want to have a line chart with Month on the X axis and the Y axis is a count of patients presenting to an ED.  

I have 4 FIN years of data.  How to I create one line that is an average of the number (count) of ED presentations by month for the first 3 years (so average the count of each FIN year for each Month); and a second line that is the current FIN year?

Thanks all - appreciate any help!

(1) Answer