| Variable | ADF test value | Significance level (critical value) | Stationary | ||
| 1% | 5% | 10% | |||
| lnRPD | −1.8349 | −3.6463 | −2.9540 | −2.6158 | unstable |
| ΔlnRPD | −4.3202 | −3.6463 | −2.9540 | −2.6158 | stable |
| Δ2lnRPD | −8.8957 | −3.6329 | −2.9484 | −2.6129 | stable |
| lnFER | −1.3488 | −3.6210 | −2.9434 | −2.6103 | unstable |
| ΔlnFER | −1.3611 | −3.6999 | −2.9762 | −2.6274 | unstable |
| Δ2lnFER | −4.3949 | −3.6999 | −2.9763 | −2.6274 | stable |
| lnFIR | −1.6972 | −3.6210 | −2.9434 | −2.6103 | unstable |
| ΔlnFIR | −6.1100 | −3.6268 | −2.9458 | −2.6115 | stable |
| Δ2lnFIR | −12.5455 | −3.6329 | −2.9484 | −2.6129 | stable |