I am trying to modify the formula below so that the cell references will calculate automatically depending on the current year. The problem is that the # of days in the 1st week changes depending on the year. This means that every year I have to manually change the cell references. I have a column named "DAY GAS" on the current sheet. The formula I have adds the values for "DAY SHIFT" Gas cost's per week. I have 52 rows of the following formulas. one for each week. Here is a 2 day example from 2016. 2017 will need a range for 7 days on the 1st row. And then the following rows ranges will have to index from there.

=SUMPRODUCT(SALES!G7:G118,(ISNUMBER(FIND("GAS",SALES!B7:B118))*ISNUMBER(FIND("DAY",SALES!C7:C118))))

=SUMPRODUCT(SALES!G119:G510,(ISNUMBER(FIND("GAS",SALES!B119:B510))*ISNUMBER(FIND("DAY",SALES!C119:C510))))

There are 56 lines between days. The sheet "SALES!" G?? contains Gas cost. "SALES!" B?? will contain a text label "GAS" and "SALES!" C?? will contain a text label "DAY SHIFT". If these conditions are present, the value in G will be summed. It seems to be mind boggling, but there are some pretty smart people on this board. It seems like someone may have had this problem before. Thank You.