-49.92% is the change from 645 to 323
Calculation steps:
[( 323 - 645 ) ÷ 645] x 100 = -49.92%
Formula
Percentage change = [(323 - 645) / 645] x 100
Subtract the new number by the original number
323 - 645 = -322
-322 ÷ 645 = -0.4992248062015504
-0.4992248062015504 x 100 = -49.92%