-91.75% is the change from 509 to 42
Calculation steps:
[( 42 - 509 ) ÷ 509] x 100 = -91.75%
Formula
Percentage change = [(42 - 509) / 509] x 100
Subtract the new number by the original number
42 - 509 = -467
-467 ÷ 509 = -0.9174852652259332
-0.9174852652259332 x 100 = -91.75%