Table 1 Descriptive statistics of participants
Age | Mean: 13.6 years (SD: 1.7 years) | ||
|---|---|---|---|
n | % | ||
Gender | Boy | 197094 | (48.8%) |
Girl | 207112 | (51.2%) | |
Country | Austria | 13636 | (3.4%) |
Belgium - Flemish | 15424 | (3.8%) | |
Belgium - French | 11304 | (2.8%) | |
Canada | 16858 | (4.2%) | |
Czech republic | 13497 | (3.3%) | |
Denmark | 15479 | (3.8%) | |
England | 17237 | (4.3%) | |
Estonia | 10360 | (2.6%) | |
Finland | 15501 | (3.8%) | |
France | 19473 | (4.8%) | |
Germany | 17716 | (4.4%) | |
Greece | 11821 | (2.9%) | |
Greenland | 3905 | (1.0%) | |
Hungary | 11305 | (2.8%) | |
Israel | 16401 | (4.1%) | |
Latvia | 11501 | (2.9%) | |
Lithuania | 15790 | (3.9%) | |
Norway | 14760 | (3.7%) | |
Poland | 16733 | (4.1%) | |
Portugal | 10580 | (2.6%) | |
Rep. of Ireland | 12163 | (3.0%) | |
Russia | 20265 | (5.0%) | |
Scotland | 16226 | (4.0%) | |
*Slovak republic | 7671 | (1.9%) | |
*Spain | 14718 | (3.6%) | |
Sweden | 12143 | (3.0%) | |
Switzerland | 14820 | (3.7%) | |
USA | 14086 | (3.5%) | |
Wales | 12833 | (3.2%) | |
Wave | 1997/98 | 122386 | (30.3%) |
2001/02 | 135067 | (33.4%) | |
2005/06 | 146756 | (36.3%) | |