2976.19% is the change from 21 to 646
Calculation steps:
[( 646 - 21 ) ÷ 21] x 100 = 2976.19%
Formula
Percentage change = [(646 - 21) / 21] x 100
Subtract the new number by the original number
646 - 21 = 625
625 ÷ 21 = 29.761904761904763
29.761904761904763 x 100 = 2976.19%