-98.18% is the change from 823 to 15
Calculation steps:
[( 15 - 823 ) ÷ 823] x 100 = -98.18%
Formula
Percentage change = [(15 - 823) / 823] x 100
Subtract the new number by the original number
15 - 823 = -808
-808 ÷ 823 = -0.9817739975698664
-0.9817739975698664 x 100 = -98.18%