-98.91% is the change from 645 to 7
Calculation steps:
[( 7 - 645 ) ÷ 645] x 100 = -98.91%
Formula
Percentage change = [(7 - 645) / 645] x 100
Subtract the new number by the original number
7 - 645 = -638
-638 ÷ 645 = -0.9891472868217054
-0.9891472868217054 x 100 = -98.91%