-19.7% is the change from 670 to 538
Calculation steps:
[( 538 - 670 ) ÷ 670] x 100 = -19.7%
Formula
Percentage change = [(538 - 670) / 670] x 100
Subtract the new number by the original number
538 - 670 = -132
-132 ÷ 670 = -0.19701492537313434
-0.19701492537313434 x 100 = -19.7%