-40.42% is the change from 851 to 507
Calculation steps:
[( 507 - 851 ) ÷ 851] x 100 = -40.42%
Formula
Percentage change = [(507 - 851) / 851] x 100
Subtract the new number by the original number
507 - 851 = -344
-344 ÷ 851 = -0.40423031727379555
-0.40423031727379555 x 100 = -40.42%