Hilmar,

There are 4 ways to express the percent difference between two values X and Y. Each one is perfectly valid:

( x - y ) / x
( x - y ) / y
( y - x ) / x
( y - x ) / y

And since they each can produce a different result one usually should show how they arrived at the difference value they are presenting.

>That is a detail that people tend to forget.
>
>Let me post an example - you understand this, but it is for the benefit of other members.
>
>Comparing the numbers 5 and 10, 5 is 50% less than 10, but 10 is 100% more than 5. The calculation is (10-5)/5 vs. (5-10)/10.