-38.14% is the change from 645 to 399
Calculation steps:
[( 399 - 645 ) ÷ 645] x 100 = -38.14%
Formula
Percentage change = [(399 - 645) / 645] x 100
Subtract the new number by the original number
399 - 645 = -246
-246 ÷ 645 = -0.3813953488372093
-0.3813953488372093 x 100 = -38.14%