99.4% is the change from 334 to 666
Calculation steps:
[( 666 - 334 ) ÷ 334] x 100 = 99.4%
Formula
Percentage change = [(666 - 334) / 334] x 100
Subtract the new number by the original number
666 - 334 = 332
332 ÷ 334 = 0.9940119760479041
0.9940119760479041 x 100 = 99.4%