51.9% is the change from 343 to 521
Calculation steps:
[( 521 - 343 ) ÷ 343] x 100 = 51.9%
Formula
Percentage change = [(521 - 343) / 343] x 100
Subtract the new number by the original number
521 - 343 = 178
178 ÷ 343 = 0.5189504373177842
0.5189504373177842 x 100 = 51.9%