-20.65% is the change from 644 to 511
Calculation steps:
[( 511 - 644 ) ÷ 644] x 100 = -20.65%
Formula
Percentage change = [(511 - 644) / 644] x 100
Subtract the new number by the original number
511 - 644 = -133
-133 ÷ 644 = -0.20652173913043478
-0.20652173913043478 x 100 = -20.65%