-99.4% is the change from 664 to 4
Calculation steps:
[( 4 - 664 ) ÷ 664] x 100 = -99.4%
Formula
Percentage change = [(4 - 664) / 664] x 100
Subtract the new number by the original number
4 - 664 = -660
-660 ÷ 664 = -0.9939759036144579
-0.9939759036144579 x 100 = -99.4%