Types and uses of population data sources in Ethiopia​

First hand data which are collected by census, vital registration, sample survey, administrative records, population register, etc are primary sources of population data. Census is the main source of demographic data. Vital Registration System (VRS) is also known as Civil Registration System.

20: 5

explanation:

about 20% of the world's population lives in   southwest asia, but on less than 5% of the world's   land area.