-19.63% is the change from 647 to 520
Calculation steps:
[( 520 - 647 ) ÷ 647] x 100 = -19.63%
Formula
Percentage change = [(520 - 647) / 647] x 100
Subtract the new number by the original number
520 - 647 = -127
-127 ÷ 647 = -0.19629057187017002
-0.19629057187017002 x 100 = -19.63%