-19.53% is the change from 215 to 173
Calculation steps:
[( 173 - 215 ) ÷ 215] x 100 = -19.53%
Formula
Percentage change = [(173 - 215) / 215] x 100
Subtract the new number by the original number
173 - 215 = -42
-42 ÷ 215 = -0.19534883720930232
-0.19534883720930232 x 100 = -19.53%