-9.09% is the change from 187 to 170
Calculation steps:
[( 170 - 187 ) ÷ 187] x 100 = -9.09%
Formula
Percentage change = [(170 - 187) / 187] x 100
Subtract the new number by the original number
170 - 187 = -17
-17 ÷ 187 = -0.09090909090909091
-0.09090909090909091 x 100 = -9.09%