Hi,

IMHO, the easiest way is to use SUBSET_SUM([Field],SUBSET([Field_Condition])), where [Field] contains value, you want to sum and [Field_Condition] is the one which holds a condition. For example, the result of SUBSET_SUM([Investment],SUBSET([Year])) will be overall value of investment in each year of you dataset. See http://www.visokio.com/kb/subset-functions.

Michal