-91.09% is the change from 999 to 89
Calculation steps:
[( 89 - 999 ) ÷ 999] x 100 = -91.09%
Formula
Percentage change = [(89 - 999) / 999] x 100
Subtract the new number by the original number
89 - 999 = -910
-910 ÷ 999 = -0.9109109109109109
-0.9109109109109109 x 100 = -91.09%