.27     2.77     0.87--12.33       23,002 (121)
  Population growth--Crude rate of natural change                                                                                    0.65     3.35     -11-9.6           23,042 (122)
  GDP at current market price: Euro per inhabitant in % of the European average                                                      84.10    52.33    12--251           23,042 (122)
  Percentage of people from an Extra-EU country                                                                                      0.03     0.03     0.001--0.13       23,042 (122)
  Percentage of people from another EU country                                                                                       0.02     0.02     0.001--0.20       23,042 (122)
  Percentage of active population holding an upper secondary degree or above                                                         0.74     0.17     0.26--0.97        23,042 (122)
  Percentage of economically active people holding a managerial or professional position                                             0.22     0.06     0.13--0.46        21,403 (111)
  Median age of population                                                                                                           40.28    2.19     34.8--46.6        23,042 (122)

Sources: ESS, EUROSTAT, QoG regional data.

To address possible sources of bias and adequately separate the role of regional factors from individual ones, on the basis of previous literature, we select and control for covariates that might affect the dependent, independent and mediation variables. In this sense, we include measures of GDP per capita, population growth, median age, percentage of migrants from inside and outside the EU, percentage of the active population (i.e. people between 25--64 years old) with a secondary degree or above, percentage of economically active population (i.e. people between 15--64 years old) holding a managerial or professional position, long-term unemployment, and regions' size at t