-35.5% is the change from 1000 to 645
Calculation steps:
[( 645 - 1000 ) ÷ 1000] x 100 = -35.5%
Formula
Percentage change = [(645 - 1000) / 1000] x 100
Subtract the new number by the original number
645 - 1000 = -355
-355 ÷ 1000 = -0.355
-0.355 x 100 = -35.5%