814.29% is the change from 70 to 640
Calculation steps:
[( 640 - 70 ) ÷ 70] x 100 = 814.29%
Formula
Percentage change = [(640 - 70) / 70] x 100
Subtract the new number by the original number
640 - 70 = 570
570 ÷ 70 = 8.142857142857142
8.142857142857142 x 100 = 814.29%