-21.72% is the change from 824 to 645
Calculation steps:
[( 645 - 824 ) ÷ 824] x 100 = -21.72%
Formula
Percentage change = [(645 - 824) / 824] x 100
Subtract the new number by the original number
645 - 824 = -179
-179 ÷ 824 = -0.21723300970873785
-0.21723300970873785 x 100 = -21.72%