Hi,

There is proberly an easier way to do it but you can use CountIf() and
Ofsett(),
Asuming your data for May 2004 is en cell B3 this should give you the
pct change

=(OFFSET(B3,COUNTIF(B3:B6,"0")-1,0)-(OFFSET(B3,COUNTIF(B3:B6,"0")-2,0)))/(OFFSET(B3,COUNTIF(B3:B6,"0")-2,0))

The difference can be calculated with the same functions:

=(OFFSET(B3,COUNTIF(B3:B6,"0")-1,0))-(OFFSET(B3,COUNTIF(B3:B6,"0")-2,0))

Best regards
Bondi