You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Swaziland

Context:
Swaziland's currency is pegged to the South African Rand, subsuming Swaziland's monetary policy to South Africa. Customs duties from the Southern African Customs Union, which may equal as much as 70% of government revenue this year, and worker remittances from South Africa substantially supplement domestically earned income. Swaziland is not poor enough to merit an IMF program; however, the country is struggling to reduce the size of the civil service and control costs at public enterprises. The government is trying to improve the atmosphere for foreign direct investment.

Question:
From where does Swaziland get customs revenue?

Southern African Customs Union