54.36% is the change from 642 to 991
Calculation steps:
[( 991 - 642 ) ÷ 642] x 100 = 54.36%
Formula
Percentage change = [(991 - 642) / 642] x 100
Subtract the new number by the original number
991 - 642 = 349
349 ÷ 642 = 0.543613707165109
0.543613707165109 x 100 = 54.36%