Level

First Difference

Variable

ADF

PP

ADF

PP

Crude oil

−1.874

−1.503

8.124**

−7.978**

Gasoline

−2.558

−2.596

10.692**

10.684**

Gas oil

−2.713

−3.079

14.992**

15.745**

RFO

−1.490

−1.144

−6.996**

−6.960**

Premix

−2.778

−2.177

−5.912**

−8.687**

Exchange rate

−0.058

−0.304

−7.393**

−7.311**

Inflation rate

0.808

0.828

−8.258**

−8.258**