-80.52% is the change from 77 to 15
Calculation steps:
[( 15 - 77 ) ÷ 77] x 100 = -80.52%
Formula
Percentage change = [(15 - 77) / 77] x 100
Subtract the new number by the original number
15 - 77 = -62
-62 ÷ 77 = -0.8051948051948052
-0.8051948051948052 x 100 = -80.52%