165.37% is the change from 309 to 820
Calculation steps:
[( 820 - 309 ) ÷ 309] x 100 = 165.37%
Formula
Percentage change = [(820 - 309) / 309] x 100
Subtract the new number by the original number
820 - 309 = 511
511 ÷ 309 = 1.6537216828478964
1.6537216828478964 x 100 = 165.37%