Period | Study period | The value of β system is estimated | Conclusions |
1 | 1990-1996 | 0.010966 | Convergence |
2 | 1997-2001 | −0.00302 | Not convergence |
3 | 2002-2007 | 0.001536 | Convergence |
4 | 1991-2007 | −0.00264 | Not convergence |