This is a bit tough and I'm covering it in my new book. What you need to do is create an array and populate each item in the array with the value from the cross-tab. The cross-tab reports from the top to the bottom so the array would just correspond to one year at a time. Then you can look at the current field value with the corresponding item in the array and if there is an increase then change the highlighting.

Yes, I know that this is a confusing explanation. But you really need to be an expert at Crystal syntax to pull it off and its way too much code to write here without messing something up. You can post follow up questions if you need more assistance.