-21.95% is the change from 647 to 505
Calculation steps:
[( 505 - 647 ) ÷ 647] x 100 = -21.95%
Formula
Percentage change = [(505 - 647) / 647] x 100
Subtract the new number by the original number
505 - 647 = -142
-142 ÷ 647 = -0.21947449768160743
-0.21947449768160743 x 100 = -21.95%