42.57% is the change from 646 to 921
Calculation steps:
[( 921 - 646 ) ÷ 646] x 100 = 42.57%
Formula
Percentage change = [(921 - 646) / 646] x 100
Subtract the new number by the original number
921 - 646 = 275
275 ÷ 646 = 0.42569659442724456
0.42569659442724456 x 100 = 42.57%