-96.99% is the change from 664 to 20
Calculation steps:
[( 20 - 664 ) ÷ 664] x 100 = -96.99%
Formula
Percentage change = [(20 - 664) / 664] x 100
Subtract the new number by the original number
20 - 664 = -644
-644 ÷ 664 = -0.9698795180722891
-0.9698795180722891 x 100 = -96.99%