3400% is the change from 19 to 665
Calculation steps:
[( 665 - 19 ) ÷ 19] x 100 = 3400%
Formula
Percentage change = [(665 - 19) / 19] x 100
Subtract the new number by the original number
665 - 19 = 646
646 ÷ 19 = 34
34 x 100 = 3400%
Example