-0.99% is the change from 101 to 100
Calculation steps:
[( 100 - 101 ) ÷ 101] x 100 = -0.99%
Formula
Percentage change = [(100 - 101) / 101] x 100
Subtract the new number by the original number
100 - 101 = -1
-1 ÷ 101 = -0.009900990099009901
-0.009900990099009901 x 100 = -0.99%