-37.5% is the change from 344 to 215
Calculation steps:
[( 215 - 344 ) ÷ 344] x 100 = -37.5%
Formula
Percentage change = [(215 - 344) / 344] x 100
Subtract the new number by the original number
215 - 344 = -129
-129 ÷ 344 = -0.375
-0.375 x 100 = -37.5%