Calculating subtotals
 

(I'm using Excel 2007)

My spreadsheet has 500,000 rows. It has column labels:
key amt1 amt2 amt3 amt4 amt5

At each change in "key", I need the sums of "amt1", "amt2", "amt3",
"amt4" "amt5".

When I use the Subtotal command in the Outline group on the Data tab,
it takes more than 10 HOURS to calculate the subtotals and grand
totals.

Is there a faster way to compute the subtotals and grand
totals?