Where can I get national debt data? I'm trying to find out about the history of South Africa's government debt. However, I couldn't manage to find suitable literature or websites showing the history. It is also very difficult to find data on the national treasury website of South Africa.
Does anybody have any hints or literature tips?
Several international organisations provide open access to macroeconomic data such as national debt - usually the World Bank, economic development organizations such as the OECD and the African Development Bank, as well as public institutions in the USA (data.gov) and in Europe (as an example the ECB data warehouse). The national central banks should also provide the data you need, but its ease of access might vary.

The World Bank Open Data has the data you need, both in LCU (local currency) or in % of GDP, but only up to 2000 for the specific case of South Africa. 

The IMF also collects data for several countries, so check if the page for South Africa has the data you are looking for.