| (1) Eastern Region | (2) Central region | (3) Western Region | |
| Total logarithmic imports | Total logarithmic imports | Total logarithmic imports | |
| VARIABLES | LnY_im | LnY_im | LnY-im |
| lnHP | 2.608*** | 5.991 | −8.688** |
| (0.574) | (3.925) | (4.150) | |
| lnHP^2 | −0.144*** | −0.344 | 0.511** |
| (0.0311) | (0.229) | (0.252) | |
| Constant | 2.122 | −18.39 | 37.95** |
| (3.948) | (21.65) | (18.30) | |
| Control variable | Y | Y | Y |
| Year fixed effect | Y | Y | Y |
| Individual fixation effect | Y | Y | Y |
| Observations | 240 | 128 | 176 |
| R-squared | 0.988 | 0.977 | 0.929 |
| Number of id | 15 | 8 | 11 |