Swaziland:

Economic growth in Swaziland has lagged behind that of its neighbours. Real GDP growth since 2001 has averaged 2.8%, nearly 2 percentage points lower than growth in other Southern African Customs Union (SACU) member countries. Low agricultural productivity in the SNLs, repeated droughts, the devastating effect of HIV/AIDS and an overly large and inefficient government sector are likely contributing factors. Swaziland's public finances deteriorated in the late 1990s following sizeable surpluses a decade earlier. A combination of declining revenues and increased spending led to significant budget deficits.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What is the average GDP of SACU member countries?
unanswerable