I'm looking for a function or something to increase values by a certain percentage in a cell that contains numerous values. In this spreadsheet. I am focusing on the "D" Column.

I have attached a spreadsheet for example:EXAMPLE.xls

The price and sale-price column are obviously easy to do. In d2 is the following:
"Size"
"2 ft x 3 ft"
"(+155) 3 ft 6 in x 5 ft 6 in"
"(+360) 5 ft x 8 ft"
"(+888) 8 ft x 11 ft"
"(+163) 2 ft 6 in x 8 ft Runner"

I'm looking for a way to increase/decrease the numbers in (+) by a certain percentage. This is a shortened spreadsheet. The regular one is about 30,000 rows. Please help!EXAMPLE.xls