| Inspection form | ADF statistics | Critical value | Conclusion | The value of P |

| (c t 1) | −4.788251 | −3.710482 | First order differential stability | 0.0074 |

| (c t 1) | −6.002737 | −3.710482 | First order differential stability | 0.0009 |

| (c t 1) | −4.846970 | −3.690814 | First order differential stability | 0.0060 |

| (c t 2) | −5.214174 | −3.710482 | Two order differential stability | 0.0034 |

| (c t 2) | −4.155943 | −3.759743 | Two order differential stability | 0.0260 |

| (c t 1) | −4.913629 | −3.690814 | First order differential stability | 0.0053 |