6560% is the change from 15 to 999
Calculation steps:
[( 999 - 15 ) ÷ 15] x 100 = 6560%
Formula
Percentage change = [(999 - 15) / 15] x 100
Subtract the new number by the original number
999 - 15 = 984
984 ÷ 15 = 65.6
65.6 x 100 = 6560%
Example