50.49% is the change from 612 to 921
Calculation steps:
[( 921 - 612 ) ÷ 612] x 100 = 50.49%
Formula
Percentage change = [(921 - 612) / 612] x 100
Subtract the new number by the original number
921 - 612 = 309
309 ÷ 612 = 0.5049019607843137
0.5049019607843137 x 100 = 50.49%