78.43% is the change from 51 to 91
Calculation steps:
[( 91 - 51 ) ÷ 51] x 100 = 78.43%
Formula
Percentage change = [(91 - 51) / 51] x 100
Subtract the new number by the original number
91 - 51 = 40
40 ÷ 51 = 0.7843137254901961
0.7843137254901961 x 100 = 78.43%