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%)

(^*Waves and countries without HBSC-SCL data: Spain 1997/98, Slovak republic 2001/02).