65.83% is the change from 521 to 864
Calculation steps:
[( 864 - 521 ) ÷ 521] x 100 = 65.83%
Formula
Percentage change = [(864 - 521) / 521] x 100
Subtract the new number by the original number
864 - 521 = 343
343 ÷ 521 = 0.6583493282149712
0.6583493282149712 x 100 = 65.83%