-78.48% is the change from 999 to 215
Calculation steps:
[( 215 - 999 ) ÷ 999] x 100 = -78.48%
Formula
Percentage change = [(215 - 999) / 999] x 100
Subtract the new number by the original number
215 - 999 = -784
-784 ÷ 999 = -0.7847847847847848
-0.7847847847847848 x 100 = -78.48%