-21.64% is the change from 647 to 507
Calculation steps:
[( 507 - 647 ) ÷ 647] x 100 = -21.64%
Formula
Percentage change = [(507 - 647) / 647] x 100
Subtract the new number by the original number
507 - 647 = -140
-140 ÷ 647 = -0.21638330757341576
-0.21638330757341576 x 100 = -21.64%