sequence	ADF test value	Significant level			P value	Stationarity
sequence	ADF test value	1%	5%	10%	P value	Stationarity
CPI	0.066846	−2.584539	−1.943540	−1.614941	0.7022	Non-stable
PPI	−0.707841	−2.583011	−1.943324	−1.615075	0.4084	Non-stable
DCPI	−6.427866	−2.584539	−1.943540	−1.614941	0.0000	smooth
DPPI	−4.920177	−2.583011	−1.943324	−1.615075	0.0000	smooth