I don't think they are self sufficient.Aus for eg has a big mining sector..
I believe Serbia has the same GDP like SL but their population is less, so the country looks bit like a developed country as more money can be spent on each citizen..
For that matter when you move into the outback of SL, you'll find that people are more self sufficient than the urban crowd..
They are poor. Not much involved to the economy.
- Education facilities are low
- No or low access to medical facilities. They have to wait months in queues for a surgery
- Those are the people who fall for pyramid schemes
- And most of them are dependant on subsidies like 'Aswesuma'
TBH, I don't know about Serbia.