-51.44% is the change from 661 to 321
Calculation steps:
[( 321 - 661 ) ÷ 661] x 100 = -51.44%
Formula
Percentage change = [(321 - 661) / 661] x 100
Subtract the new number by the original number
321 - 661 = -340
-340 ÷ 661 = -0.5143721633888049
-0.5143721633888049 x 100 = -51.44%