1940% is the change from 15 to 306
Calculation steps:
[( 306 - 15 ) ÷ 15] x 100 = 1940%
Formula
Percentage change = [(306 - 15) / 15] x 100
Subtract the new number by the original number
306 - 15 = 291
291 ÷ 15 = 19.4
19.4 x 100 = 1940%
Example