-5.47% is the change from 128 to 121
Calculation steps:
[( 121 - 128 ) ÷ 128] x 100 = -5.47%
Formula
Percentage change = [(121 - 128) / 128] x 100
Subtract the new number by the original number
121 - 128 = -7
-7 ÷ 128 = -0.0546875
-0.0546875 x 100 = -5.47%