-87.6% is the change from 121 to 15
Calculation steps:
[( 15 - 121 ) ÷ 121] x 100 = -87.6%
Formula
Percentage change = [(15 - 121) / 121] x 100
Subtract the new number by the original number
15 - 121 = -106
-106 ÷ 121 = -0.8760330578512396
-0.8760330578512396 x 100 = -87.6%