-99.7% is the change from 663 to 2
Calculation steps:
[( 2 - 663 ) ÷ 663] x 100 = -99.7%
Formula
Percentage change = [(2 - 663) / 663] x 100
Subtract the new number by the original number
2 - 663 = -661
-661 ÷ 663 = -0.9969834087481146
-0.9969834087481146 x 100 = -99.7%