-21.63% is the change from 661 to 518
Calculation steps:
[( 518 - 661 ) ÷ 661] x 100 = -21.63%
Formula
Percentage change = [(518 - 661) / 661] x 100
Subtract the new number by the original number
518 - 661 = -143
-143 ÷ 661 = -0.21633888048411498
-0.21633888048411498 x 100 = -21.63%