76.78% is the change from 521 to 921
Calculation steps:
[( 921 - 521 ) ÷ 521] x 100 = 76.78%
Formula
Percentage change = [(921 - 521) / 521] x 100
Subtract the new number by the original number
921 - 521 = 400
400 ÷ 521 = 0.7677543186180422
0.7677543186180422 x 100 = 76.78%