-17.89% is the change from 816 to 670
Calculation steps:
[( 670 - 816 ) ÷ 816] x 100 = -17.89%
Formula
Percentage change = [(670 - 816) / 816] x 100
Subtract the new number by the original number
670 - 816 = -146
-146 ÷ 816 = -0.17892156862745098
-0.17892156862745098 x 100 = -17.89%