Skolelevers drogvanor - 2006 B, gymnasiets år 2

Since 1971, a national drug habit survey has been conducted among Swedish ninth graders. From 2004, annual survey are also being conducted among students in the second year of...

自1971年起，一项面向瑞典九年级学生的全国药物使用习惯调查（national drug habit survey）便持续开展。自2004年起，同时面向……二年级学生开展年度调查。