[1
]Department of Statistics and Econometrics, Bucharest University of Economic Studies,
Bucharest, Romania
[2
]Institute of National Economy – Romanian Academy, Bucharest, Romania
[3
]Department of Cybernetics, Economic Informatics, Finance and Accounting, Petroleum-Gas
University of Ploiesti, Ploiești, Romania
[4
]Department of Economics,” Dunărea de Jos”, University of Galați, Galați, Romania