Pivot table % Difference From (previous)
 

I have a Pivot table summurizing data where years and quarter are in the row
label and average af amount in Values:
Values
Years Date Average of Amount $2 % diff previous Q
2005 Qtr3 $283.96
Qtr4 $344.83 21.43%

2006 Qtr1 $462.70
Qtr2 $603.55 30.44%
Qtr3 $665.53 10.27%
Qtr4 $674.41 1.33%

2007 Qtr1 $665.95

I run % difference from (previous), but i can't get say Q1 2006 % Difference
from the previus Q (Q4 2005) and the same for every Q1 with respect of the Q4
of previous year, all the rest of course works fine. Any hints?
thanks
Andrea