| Variables | Level | First difference | Integration order (unit root) | ||
| ADF | PP | ADF Z(t) (pval) | PP | ||
| lenc | 1.12 (0.99) | −1.65 (0.76) | −3.4 (0.01) | −5.33 (0.00) | I~(1) |
| lpib | 0.23 (0.93) | 0.33 (0.97) | −5.50 (0.00) | −5.43 (0.00) | I~(1) |
| lpop | −2.95 (0.14) | −6.79 (0.00) | −2.84 (0.050) | −3.584 (0.03) | I~(1) |