-85.09% is the change from 664 to 99
Calculation steps:
[( 99 - 664 ) ÷ 664] x 100 = -85.09%
Formula
Percentage change = [(99 - 664) / 664] x 100
Subtract the new number by the original number
99 - 664 = -565
-565 ÷ 664 = -0.8509036144578314
-0.8509036144578314 x 100 = -85.09%