675.9% is the change from 83 to 644
Calculation steps:
[( 644 - 83 ) ÷ 83] x 100 = 675.9%
Formula
Percentage change = [(644 - 83) / 83] x 100
Subtract the new number by the original number
644 - 83 = 561
561 ÷ 83 = 6.759036144578313
6.759036144578313 x 100 = 675.9%