[1] Inst Natl Stat & Etud Econ STATEC, Unit EPR2, L-2013 Luxembourg, Luxembourg
[2] CREST Timbre J390, F-92245 Malakoff, France
[3] Maastricht Univ, UNU MERIT, NL-6200 MD Maastricht, Netherlands
[4] Univ Maastricht, CIRANO, NL-6200 MD Maastricht, Netherlands
[5] Maastricht Univ, Dept Quantitat Econ, NL-6200 MD Maastricht, Netherlands