-60.61% is the change from 660 to 260
Calculation steps:
[( 260 - 660 ) ÷ 660] x 100 = -60.61%
Formula
Percentage change = [(260 - 660) / 660] x 100
Subtract the new number by the original number
260 - 660 = -400
-400 ÷ 660 = -0.6060606060606061
-0.6060606060606061 x 100 = -60.61%