-19.1% is the change from 644 to 521
Calculation steps:
[( 521 - 644 ) ÷ 644] x 100 = -19.1%
Formula
Percentage change = [(521 - 644) / 644] x 100
Subtract the new number by the original number
521 - 644 = -123
-123 ÷ 644 = -0.19099378881987578
-0.19099378881987578 x 100 = -19.1%