-30.97% is the change from 930 to 642
Calculation steps:
[( 642 - 930 ) ÷ 930] x 100 = -30.97%
Formula
Percentage change = [(642 - 930) / 930] x 100
Subtract the new number by the original number
642 - 930 = -288
-288 ÷ 930 = -0.3096774193548387
-0.3096774193548387 x 100 = -30.97%