Sorry, the tabulation got all screwed up in the above posting and I don't
know how to fix it.

The explanation is:

-Column A=Bill_Date, B=Usage, C to F=Charge1 to Charge4, G=Total_Charge
-From 2-Mar-05 to 5-Jun-06, no data for Charge1 to Charge4
-From 4-Sep-06 to 1-Jun-07, no data in Charge4
-From 5-Dec-08 to 4-Jun-09, no data in Charge2 and Charge4

Thanks.
--
Maki @ Canberra.AU