The unemployment rate is also a determinant of economic growth. Due to data availability, the unemployment
rate at county level has been included. We acknowledge the limitation of doing so, as we presume that in time of
crises the unemployment rate might increase at a faster pace outside the growth poles. We have no information
available to confirm our assumption. Furthermore, it has been noticed that the unemployment rates at regional level
have the same trend as at national level, and accordingly we assume that their evolution at regional level reflects
best the evolution at local level. Therefore, the unemployment rate at county level has been considered as a reliable
substitute for the missing data.