Switzerland:

In 2006, Switzerland approved 1 billion francs of supportive investment in the poorer Southern and Central European countries in support of cooperation and positive ties to the EU as a whole. A further referendum will be needed to approve 300 million francs to support Romania and Bulgaria and their recent admission. The Swiss have also been under EU and sometimes international pressure to reduce banking secrecy and to raise tax rates to parity with the EU. Preparatory discussions are being opened in four new areas: opening up the electricity market, participation in the European GNSS project Galileo, cooperating with the European centre for disease prevention and recognising certificates of origin for food products.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". In 2006, what did Switzerland approve 1 billion francs of supportive investment for?
poorer Southern and Central European countries