-83.66% is the change from 606 to 99
Calculation steps:
[( 99 - 606 ) ÷ 606] x 100 = -83.66%
Formula
Percentage change = [(99 - 606) / 606] x 100
Subtract the new number by the original number
99 - 606 = -507
-507 ÷ 606 = -0.8366336633663366
-0.8366336633663366 x 100 = -83.66%