-19.41% is the change from 819 to 660
Calculation steps:
[( 660 - 819 ) ÷ 819] x 100 = -19.41%
Formula
Percentage change = [(660 - 819) / 819] x 100
Subtract the new number by the original number
660 - 819 = -159
-159 ÷ 819 = -0.19413919413919414
-0.19413919413919414 x 100 = -19.41%