-97.98% is the change from 645 to 13
Calculation steps:
[( 13 - 645 ) ÷ 645] x 100 = -97.98%
Formula
Percentage change = [(13 - 645) / 645] x 100
Subtract the new number by the original number
13 - 645 = -632
-632 ÷ 645 = -0.9798449612403101
-0.9798449612403101 x 100 = -97.98%