-96.1% is the change from 666 to 26
Calculation steps:
[( 26 - 666 ) ÷ 666] x 100 = -96.1%
Formula
Percentage change = [(26 - 666) / 666] x 100
Subtract the new number by the original number
26 - 666 = -640
-640 ÷ 666 = -0.960960960960961
-0.960960960960961 x 100 = -96.1%