-51.01% is the change from 990 to 485
Calculation steps:
[( 485 - 990 ) ÷ 990] x 100 = -51.01%
Formula
Percentage change = [(485 - 990) / 990] x 100
Subtract the new number by the original number
485 - 990 = -505
-505 ÷ 990 = -0.51010101010101
-0.51010101010101 x 100 = -51.01%