Create calculated fields for all of the 3 quarters above.
Q1 2016 = IF YEAR([Month/Year]) = 2016 AND DATEPART('quarter',[Month/Year])= 1 THEN [Sales] END
Amend that formula for the other quarters.
Then create calculated fields for your % difference fields.
Your QonQ formula would be: SUM([Q22016])/SUM([Q12016]) - 1
The end results looks as follows:
Awesome, Thank you very much.