-78.57% is the change from 644 to 138
Calculation steps:
[( 138 - 644 ) ÷ 644] x 100 = -78.57%
Formula
Percentage change = [(138 - 644) / 644] x 100
Subtract the new number by the original number
138 - 644 = -506
-506 ÷ 644 = -0.7857142857142857
-0.7857142857142857 x 100 = -78.57%