-67.86% is the change from 28 to 9
Calculation steps:
[( 9 - 28 ) ÷ 28] x 100 = -67.86%
Formula
Percentage change = [(9 - 28) / 28] x 100
Subtract the new number by the original number
9 - 28 = -19
-19 ÷ 28 = -0.6785714285714286
-0.6785714285714286 x 100 = -67.86%