Perhaps you should try some spelling variations:
population census » population density, population densities
6.2 communication » 3.2 communication, 2.3 communication, 2.7 communication
technology 21st » technology 2.1.1, technology 2.1.2, technology 2.1.3
21st population » host population, fast population, list population
developing a » developing _
prices 6.2 » prices 3.2, prices 4.2, prices 5.2
a afrique » l afrique, en afrique

You may be able to get more results by adjusting your search query.

• Adding a wildcard symbol may retrieve word variants: technology 21st population census prices 6.2 communication costs _ developing a afrique.*.