-99% is the change from 997 to 10
Calculation steps:
[( 10 - 997 ) ÷ 997] x 100 = -99%
Formula
Percentage change = [(10 - 997) / 997] x 100
Subtract the new number by the original number
10 - 997 = -987
-987 ÷ 997 = -0.9899699097291875
-0.9899699097291875 x 100 = -99%