-40.07% is the change from 866 to 519
Calculation steps:
[( 519 - 866 ) ÷ 866] x 100 = -40.07%
Formula
Percentage change = [(519 - 866) / 866] x 100
Subtract the new number by the original number
519 - 866 = -347
-347 ÷ 866 = -0.4006928406466513
-0.4006928406466513 x 100 = -40.07%