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...
Ghana Round 4 Service Delivery Point (SQ) survey used a two-stage cluster design with urban and rural, major ecological zones as the strata. A sample of 100 enumeration areas (EAs) was drawn by the Gh
Johns Hopkins Research Data Repository2024-12-20 更新30