How to use total to calculate a value??

[#1]

Hi, I have this numbers:

Year Suscribers Ordinal year

2004 331 1

2005 249 2

2006 208 3

2007 189 4

2008 171 5

2009 135 6

And this others:

Years Desertion

2004-2005 82

2005-2006 42

2006-2007 24

2007-2008 16

2008-2009 25

I want to calculate the percentage that is for example: 82(desertion, ordinal year = 2) / 331(suscribers, ordinal year = 1)

but I have the problem that in the expressions I have I get 82 / 249 (the same ordinal year)

I have two expressions, one of this is a ciclyc expresion.

In one I have: sum(Desertionl)

And in the ciclyc I have:

sum(Desertion) / sum(total <Ordinal Year, Plan > Suscribers )

and sum(Desertion)

Thanks in advance.