-17.07% is the change from 123 to 102
Calculation steps:
[( 102 - 123 ) ÷ 123] x 100 = -17.07%
Formula
Percentage change = [(102 - 123) / 123] x 100
Subtract the new number by the original number
102 - 123 = -21
-21 ÷ 123 = -0.17073170731707318
-0.17073170731707318 x 100 = -17.07%