In the 70s Norway was amongst the poorest European countries. By the opening of oil and gas plants, the country achieved great economic success. According to a survey between 2001 and 2006, Norway had the highest standard of living in the world. The country's balance of payments is positive; its biggest export partner is the European Union. Norway is the 8th largest gas extractor and the 16th largest oil extractor on the planet. Apart from the gas and oil export their fish export is huge, as well as the export of mechanical engineering goods. The Kingdom of Norway is part of the NATO since 1949 and the European Free Trade Association (EFTA) since 1960. The Norwegians have twice rejected the referendum to join the European Union, even though they are part of the European Economic Area (EEA) and the Schengen countries too.