-79.8% is the change from 505 to 102
Calculation steps:
[( 102 - 505 ) ÷ 505] x 100 = -79.8%
Formula
Percentage change = [(102 - 505) / 505] x 100
Subtract the new number by the original number
102 - 505 = -403
-403 ÷ 505 = -0.7980198019801981
-0.7980198019801981 x 100 = -79.8%