-9.9% is the change from 1000 to 901
Calculation steps:
[( 901 - 1000 ) ÷ 1000] x 100 = -9.9%
Formula
Percentage change = [(901 - 1000) / 1000] x 100
Subtract the new number by the original number
901 - 1000 = -99
-99 ÷ 1000 = -0.099
-0.099 x 100 = -9.9%