-35.7% is the change from 1000 to 643
Calculation steps:
[( 643 - 1000 ) ÷ 1000] x 100 = -35.7%
Formula
Percentage change = [(643 - 1000) / 1000] x 100
Subtract the new number by the original number
643 - 1000 = -357
-357 ÷ 1000 = -0.357
-0.357 x 100 = -35.7%