-79.08% is the change from 521 to 109
Calculation steps:
[( 109 - 521 ) ÷ 521] x 100 = -79.08%
Formula
Percentage change = [(109 - 521) / 521] x 100
Subtract the new number by the original number
109 - 521 = -412
-412 ÷ 521 = -0.7907869481765835
-0.7907869481765835 x 100 = -79.08%