Socioeconomic characteristics by country and for the total sample (%).

All results are presented in percent save for the mean age that is presented in years.a This education category encompasses participants who have obtained a degree equivalent to 3 or 4 years of additional studies after the completion of high school.b In the United Kingdom, all monetary units were presented in equivalent pounds £.c Net income represents the income after taxes.Socioeconomic characteristics by country and for the total sample (%).