Question: When did Denmark join the union that has completely surrounded Switzerland and Liechtenstein since 1995?

full_context: Document 1: Switzerland: A large number of international institutions have their seats in Switzerland, in part because of its policy of neutrality. Geneva is the birthplace of the Red Cross and Red Crescent Movement and the Geneva Conventions and, since 2006, hosts the United Nations Human Rights Council. Even though Switzerland is one of the most recent countries to have joined the United Nations, the Palace of Nations in Geneva is the second biggest centre for the United Nations after New York, and Switzerland was a founding member and home to the League of Nations.
Document 2: Switzerland: The establishment of the Swiss Confederation is traditionally dated to 1 August 1291, which is celebrated annually as the Swiss National Day. The country has a long history of armed neutrality—it has not been in a state of war internationally since 1815—and did not join the United Nations until 2002. Nevertheless, it pursues an active foreign policy and is frequently involved in peace-building processes around the world. In addition to being the birthplace of the Red Cross, Switzerland is home to numerous international organizations, including the second largest UN office. On the European level, it is a founding member of the European Free Trade Association, but notably it is not part of the European Union, nor the European Economic Area. However the country does participate in the Schengen Area and the EU's single market through a number of bilateral treaties.
Document 3: Switzerland: Switzerland voted against membership in the European Economic Area in a referendum in December 1992 and has since maintained and developed its relationships with the European Union (EU) and European countries through bilateral agreements. In March 2001, the Swiss people refused in a popular vote to start accession negotiations with the EU. In recent years, the Swiss have brought their economic practices largely into conformity with those of the EU in many ways, in an effort to enhance their international competitiveness. The economy grew at 3% in 2010, 1.9% in 2011, and 1% in 2012. Full EU membership is a long-term objective of some in the Swiss government, but there is considerable popular sentiment against this supported by the conservative SVP party. The western French-speaking areas and the urban regions of the rest of the country tend to be more pro-EU, however with far from any significant share of the population.
Document 4: Switzerland: In 2002 Switzerland became a full member of the United Nations, leaving the Vatican City as the last widely recognised state without full UN membership. Switzerland is a founding member of the EFTA, but is not a member of the European Economic Area. An application for membership in the European Union was sent in May 1992, but not advanced since the EEA was rejected in December 1992 when Switzerland was the only country to launch a referendum on the EEA. There have since been several referenda on the EU issue; due to a mixed reaction from the population the membership application has been frozen. Nonetheless, Swiss law is gradually being adjusted to conform with that of the EU, and the government has signed a number of bilateral agreements with the European Union. Switzerland, together with Liechtenstein, has been completely surrounded by the EU since Austria's entry in 1995. On 5 June 2005, Swiss voters agreed by a 55% majority to join the Schengen treaty, a result that was regarded by EU commentators as a sign of support by Switzerland, a country that is traditionally perceived as independent and reluctant to enter supranational bodies.
Document 5: European Union law: The Social Charter was subsequently adopted in 1989 by 11 of the then 12 member states. The UK refused to sign the Social Charter and was exempt from the legislation covering Social Charter issues unless it agreed to be bound by the legislation. The UK subsequently was the only member state to veto the Social Charter being included as the "Social Chapter" of the 1992 Maastricht Treaty - instead, an Agreement on Social Policy was added as a protocol. Again, the UK was exempt from legislation arising from the protocol, unless it agreed to be bound by it. The protocol was to become known as "Social Chapter", despite not actually being a chapter of the Maastricht Treaty. To achieve aims of the Agreement on Social Policy the European Union was to "support and complement" the policies of member states. The aims of the Agreement on Social Policy are:
Document 6: European Union law: The principal Treaties that form the European Union began with common rules for coal and steel, and then atomic energy, but more complete and formal institutions were established through the Treaty of Rome 1957 and the Maastricht Treaty 1992 (now: TFEU). Minor amendments were made during the 1960s and 1970s. Major amending treaties were signed to complete the development of a single, internal market in the Single European Act 1986, to further the development of a more social Europe in the Treaty of Amsterdam 1997, and to make minor amendments to the relative power of member states in the EU institutions in the Treaty of Nice 2001 and the Treaty of Lisbon 2007. Since its establishment, more member states have joined through a series of accession treaties, from the UK, Ireland, Denmark and Norway in 1972 (though Norway did not end up joining), Greece in 1979, Spain and Portugal 1985, Austria, Finland, Norway and Sweden in 1994 (though again Norway failed to join, because of lack of support in the referendum), the Czech Republic, Cyprus, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia in 2004, Romania and Bulgaria in 2007 and Croatia in 2013. Greenland signed a Treaty in 1985 giving it a special status.
Document 7: 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.
Document 8: European Union law: EU Competition law has its origins in the European Coal and Steel Community (ECSC) agreement between France, Italy, Belgium, the Netherlands, Luxembourg and Germany in 1951 following the second World War. The agreement aimed to prevent Germany from re-establishing dominance in the production of coal and steel as members felt that its dominance had contributed to the outbreak of the war. Article 65 of the agreement banned cartels and article 66 made provisions for concentrations, or mergers, and the abuse of a dominant position by companies. This was the first time that competition law principles were included in a plurilateral regional agreement and established the trans-European model of competition law. In 1957 competition rules were included in the Treaty of Rome, also known as the EC Treaty, which established the European Economic Community (EEC). The Treaty of Rome established the enactment of competition law as one of the main aims of the EEC through the "institution of a system ensuring that competition in the common market is not distorted". The two central provisions on EU competition law on companies were established in article 85, which prohibited anti-competitive agreements, subject to some exemptions, and article 86 prohibiting the abuse of dominant position. The treaty also established principles on competition law for member states, with article 90 covering public undertakings, and article 92 making provisions on state aid. Regulations on mergers were not included as member states could not establish consensus on the issue at the time.
Document 9: European Union law: The primary law of the EU consists mainly of the founding treaties, the "core" treaties being the Treaty on European Union (TEU) and the Treaty on the Functioning of the European Union (TFEU). The Treaties contain formal and substantive provisions, which frame policies of the European Union institutions and determine the division of competences between the European Union and its member states. The TEU establishes that European Union law applies to the metropolitan territories of the member states, as well as certain islands and overseas territories, including Madeira, the Canary Islands and the French overseas departments. European Union law also applies in territories where a member state is responsible for external relations, for example Gibraltar and the Åland islands. The TEU allows the European Council to make specific provisions for regions, as for example done for customs matters in Gibraltar and Saint-Pierre-et-Miquelon. The TEU specifically excludes certain regions, for example the Faroe Islands, from the jurisdiction of European Union law. Treaties apply as soon as they enter into force, unless stated otherwise, and are generally concluded for an unlimited period. The TEU provides that commitments entered into by the member states between themselves before the treaty was signed no longer apply.[vague] All EU member states are regarded as subject to the general obligation of the principle of cooperation, as stated in the TEU, whereby member states are obliged not to take measure which could jeopardise the attainment of the TEU objectives. The Court of Justice of the European Union can interpret the Treaties, but it cannot rule on their validity, which is subject to international law. Individuals may rely on primary law in the Court of Justice of the European Union if the Treaty provisions have a direct effect and they are sufficiently clear, precise and unconditional.
Document 10: Treaties of the European Union: Two core functional treaties, the Treaty on European Union (originally signed in Maastricht in 1992) and the Treaty on the Functioning of the European Union (originally signed in Rome in 1957 as the Treaty establishing the European Economic Community), lay out how the EU operates, and there are a number of satellite treaties which are interconnected with them. The treaties have been repeatedly amended by other treaties over the 65 years since they were first signed. The consolidated version of the two core treaties is regularly published by the European Commission.
Document 11: European Union law: The Social Chapter is a chapter of the 1997 Treaty of Amsterdam covering social policy issues in European Union law. The basis for the Social Chapter was developed in 1989 by the "social partners" representatives, namely UNICE, the employers' confederation, the European Trade Union Confederation (ETUC) and CEEP, the European Centre of Public Enterprises. A toned down version was adopted as the Social Charter at the 1989 Strasbourg European Council. The Social Charter declares 30 general principles, including on fair remuneration of employment, health and safety at work, rights of disabled and elderly, the rights of workers, on vocational training and improvements of living conditions. The Social Charter became the basis for European Community legislation on these issues in 40 pieces of legislation.
Document 12: Switzerland: Switzerland joined the Council of Europe in 1963. In 1979 areas from the canton of Bern attained independence from the Bernese, forming the new canton of Jura. On 18 April 1999 the Swiss population and the cantons voted in favour of a completely revised federal constitution.In 2002 Switzerland became a full member of the United Nations, leaving the Vatican City as the last widely recognised state without full UN membership. Switzerland is a founding member of the EFTA, but is not a member of the European Economic Area. An application for membership in the European Union was sent in May 1992, but not advanced since the EEA was rejected in December 1992 when Switzerland was the only country to launch a referendum on the EEA. There have since been several referendums on the EU issue; due to opposition from the citizens, the membership application has been withdrawn. Nonetheless, Swiss law is gradually being adjusted to conform with that of the EU, and the government has signed a number of bilateral agreements with the European Union. Switzerland, together with Liechtenstein, has been completely surrounded by the EU since Austria's entry in 1995. On 5 June 2005, Swiss voters agreed by a 55% majority to join the Schengen treaty, a result that was regarded by EU commentators as a sign of support by Switzerland, a country that is traditionally perceived as independent and reluctant to enter supranational bodies.
Document 13: Switzerland: Traditionally, Switzerland avoids alliances that might entail military, political, or direct economic action and has been neutral since the end of its expansion in 1515. Its policy of neutrality was internationally recognised at the Congress of Vienna in 1815. Only in 2002 did Switzerland become a full member of the United Nations and it was the first state to join it by referendum. Switzerland maintains diplomatic relations with almost all countries and historically has served as an intermediary between other states. Switzerland is not a member of the European Union; the Swiss people have consistently rejected membership since the early 1990s. However, Switzerland does participate in the Schengen Area.
Document 14: History of the European Union: On 1 November 1993, under the third Delors Commission, the Maastricht Treaty became effective, creating the European Union with its pillar system, including foreign and home affairs alongside the European Community. The 1994 European elections were held resulting in the Socialist group maintaining their position as the largest party in Parliament. The Council proposed Jacques Santer as Commission President but he was seen as a second choice candidate, undermining his position. Parliament narrowly approved Santer but his commission gained greater support, being approved by 416 votes to 103. Santer had to use his new powers under Maastricht to flex greater control over his choice of Commissioners. They took office on 23 January 1995.
Document 15: Accession of Turkey to the European Union: Turkey's application to accede to the European Economic Community, the predecessor of the European Union (EU), was made on 14 April 1987. After the ten founding members, Turkey was one of the first countries to become a member of the Council of Europe in 1949. The country has also been an associate member of the Western European Union from 1992 to its end in 2011. Turkey signed a Customs Union agreement with the EU in 1995 and was officially recognised as a candidate for full membership on 12 December 1999, at the Helsinki summit of the European Council.
ground_truth: 1972
sub_queries: What has completely surrounded Switzerland and Liechtenstein since 1995? Answer: the EU
When did Denmark join the the EU ? Answer: 1972