-0.75% is the change from 400 to 397
Calculation steps:
[( 397 - 400 ) ÷ 400] x 100 = -0.75%
Formula
Percentage change = [(397 - 400) / 400] x 100
Subtract the new number by the original number
397 - 400 = -3
-3 ÷ 400 = -0.0075
-0.0075 x 100 = -0.75%