-85.4% is the change from 678 to 99
Calculation steps:
[( 99 - 678 ) ÷ 678] x 100 = -85.4%
Formula
Percentage change = [(99 - 678) / 678] x 100
Subtract the new number by the original number
99 - 678 = -579
-579 ÷ 678 = -0.8539823008849557
-0.8539823008849557 x 100 = -85.4%