percentage change in … from … calculates the percentage change between two values. For example, given the following case fragment:

           01 Jun 03    20 Jun 03    30 Jun 03    15 Oct 03    02 Nov 03
HDL           2.0          2.1          1.2          2.0          2.4
LDL                        6.2          4.7                       3.1
Trig          3.6                                    3.6
LipidDrug     N                         Y            Y

percentage change in HDL from second most recent HDL is 20

percentage change in LDL from max LDL is -50