-50.5% is the change from 400 to 198
Calculation steps:
[( 198 - 400 ) ÷ 400] x 100 = -50.5%
Formula
Percentage change = [(198 - 400) / 400] x 100
Subtract the new number by the original number
198 - 400 = -202
-202 ÷ 400 = -0.505
-0.505 x 100 = -50.5%