Task: Question Generation
Input (English): The government has established an Integration Office under the Department of Foreign Affairs and the Department of Economic Affairs. To minimise the negative consequences of Switzerland's isolation from the rest of Europe, Bern and Brussels signed seven bilateral agreements to further liberalise trade ties. These agreements were signed in 1999 and took effect in 2001. This first series of bilateral agreements included the free movement of persons. A second series covering nine areas was signed in 2004 and has since been ratified, which includes the Schengen Treaty and the Dublin Convention besides others. They continue to discuss further areas for cooperation.
Output (English): When was a second series of 9 bilateral agreements signed?