31.78% is the change from 645 to 850
Calculation steps:
[( 850 - 645 ) ÷ 645] x 100 = 31.78%
Formula
Percentage change = [(850 - 645) / 645] x 100
Subtract the new number by the original number
850 - 645 = 205
205 ÷ 645 = 0.3178294573643411
0.3178294573643411 x 100 = 31.78%