-19.78% is the change from 647 to 519
Calculation steps:
[( 519 - 647 ) ÷ 647] x 100 = -19.78%
Formula
Percentage change = [(519 - 647) / 647] x 100
Subtract the new number by the original number
519 - 647 = -128
-128 ÷ 647 = -0.19783616692426584
-0.19783616692426584 x 100 = -19.78%