-97.79% is the change from 679 to 15
Calculation steps:
[( 15 - 679 ) ÷ 679] x 100 = -97.79%
Formula
Percentage change = [(15 - 679) / 679] x 100
Subtract the new number by the original number
15 - 679 = -664
-664 ÷ 679 = -0.9779086892488954
-0.9779086892488954 x 100 = -97.79%