1980% is the change from 15 to 312
Calculation steps:
[( 312 - 15 ) ÷ 15] x 100 = 1980%
Formula
Percentage change = [(312 - 15) / 15] x 100
Subtract the new number by the original number
312 - 15 = 297
297 ÷ 15 = 19.8
19.8 x 100 = 1980%
Example