-33.9% is the change from 1000 to 661
Calculation steps:
[( 661 - 1000 ) ÷ 1000] x 100 = -33.9%
Formula
Percentage change = [(661 - 1000) / 1000] x 100
Subtract the new number by the original number
661 - 1000 = -339
-339 ÷ 1000 = -0.339
-0.339 x 100 = -33.9%