-51.18% is the change from 850 to 415
Calculation steps:
[( 415 - 850 ) ÷ 850] x 100 = -51.18%
Formula
Percentage change = [(415 - 850) / 850] x 100
Subtract the new number by the original number
415 - 850 = -435
-435 ÷ 850 = -0.5117647058823529
-0.5117647058823529 x 100 = -51.18%