-19.09% is the change from 817 to 661
Calculation steps:
[( 661 - 817 ) ÷ 817] x 100 = -19.09%
Formula
Percentage change = [(661 - 817) / 817] x 100
Subtract the new number by the original number
661 - 817 = -156
-156 ÷ 817 = -0.1909424724602203
-0.1909424724602203 x 100 = -19.09%