91.75% is the change from 521 to 999
Calculation steps:
[( 999 - 521 ) ÷ 521] x 100 = 91.75%
Formula
Percentage change = [(999 - 521) / 521] x 100
Subtract the new number by the original number
999 - 521 = 478
478 ÷ 521 = 0.9174664107485605
0.9174664107485605 x 100 = 91.75%