These numerical data were obtained from an existing international study named Health Behavior in School-aged Children (HBSC), which collects information about welfare, health, social environment and living conditions of adolescent.
Öll töluleg gögn voru fengin frá fyrri rannsókn sem framkvæmd var á vegum (HBSC), þar sem gögnum um velferð, heilsu, félagslegt umhverfi og lífsskilyrði unglinga er safnað.