Table 4: PP unit root test for stationarity.

LevelFirst difference
InterceptIntercept plus trendInterceptIntercept plus trend

EXPG 1.533520−2.528736−6.392610***−7.270672***
FDIG−1.505811−2.953038−6.193253***−6.035065***
GFCG−3.280270**−6.152219***−16.95955***−17.41754***
EXR−0.650537−1.995489−3.472748***−3.349969**
PDEN−2.468145 −2.136851−3.091485**−3.289305**

Note: the Mackinnon [46] critical values are −3.699871 and −2.976263 at 1% and 5% levels of significance, respectively. ***indicates significance at the 1% level and **at the 5% level.