-39.95% is the change from 851 to 511
Calculation steps:
[( 511 - 851 ) ÷ 851] x 100 = -39.95%
Formula
Percentage change = [(511 - 851) / 851] x 100
Subtract the new number by the original number
511 - 851 = -340
-340 ÷ 851 = -0.399529964747356
-0.399529964747356 x 100 = -39.95%