Question: What years did Margrethe II of Denmark's mother rule as Queen of Denmark?

full_context: Document 1: Princess Benedikte of Denmark: Princess Benedikte of Denmark, Princess of Sayn-Wittgenstein-Berleburg {'1': ", '2': ", '3': 'RE, SKmd, D.Ht.', '4': "} (Benedikte Astrid Ingeborg Ingrid, born 29 April 1944) is the second daughter of King Frederick IX of Denmark and Ingrid of Sweden. She is the younger sister of the reigning Queen of Denmark, Margrethe II, and the older sister of Queen Anne-Marie of Greece.
Document 2: House of Monpezat: The House of Laborde de Monpezat (] ) is a French family, known since the seventeenth century, associated with the Danish Royal Family by marriage after 1967, when Henri de Laborde de Monpezat wed Princess Margrethe of Denmark, heir presumptive of the ruling House of Glücksburg. In the event of ascension to the Danish throne of their son or male-line descendant, the main branch of the Danish Royal Family will belong patrilineally to the "Laborde de Monpezat" lineage. However, it is unclear which name the royal family will use in this event.
Document 3: Succession to the Danish throne: The Danish Act of Succession, adopted on 27 March 1953, restricts the throne to those descended from Christian X and his wife, Alexandrine of Mecklenburg-Schwerin, through approved marriages. Succession is governed by absolute primogeniture.
Document 4: Alexandrine of Mecklenburg-Schwerin: Alexandrine of Mecklenburg-Schwerin (24 December 1879 – 28 December 1952) was Queen of Denmark as the spouse of King Christian X. She was also Queen of Iceland from 1 December 1918 to 17 June 1944.
Document 5: Princess Thyra of Denmark (1880–1945): Princess Thyra of Denmark and Iceland (Thyra Louise Caroline Amalie Augusta Elisabeth; Copenhagen, 14 March 1880 – Copenhagen, 2 November 1945) was the sixth child and third daughter of Frederick VIII of Denmark and his wife, Princess Louise of Sweden and Norway.
Document 6: Princess Margaretha of Sweden: Princess Margaretha of Sweden (Margaretha Sofia Lovisa Ingeborg; 25 June 1899 – 4 January 1977) was a member of the Swedish Royal Family and a Princess of Denmark by marriage, the eldest sister of Märtha, Crown Princess of Norway, Queen Astrid of the Belgians and Prince Carl Bernadotte.
Document 7: Mary, Crown Princess of Denmark: Mary, Crown Princess of Denmark, Countess of Monpezat, {'1': ", '2': ", '3': 'R.E.', '4': "} (Mary Elizabeth; "née" Donaldson; born 5 February 1972) is the wife of Frederik, Crown Prince of Denmark. Frederik is the heir apparent to the throne, which means that should Frederik succeed, she will automatically become Queen of Denmark.
Document 8: Ingrid von Rosen: Ingrid von Rosen (sometimes cited as Ingrid Bergman; 17 January 1930 – 20 May 1995) was married to Swedish film director Ingmar Bergman. Born Ingrid Karlebo in Stockholm in 1930, she was married to the Swedish count Jan-Carl von Rosen in 1953. In 1971 she married Ingmar Bergman. Ingrid von Rosen died of stomach cancer in 1995, aged 65.
Document 9: Margrethe II of Denmark: Margrethe II (Danish: "Margrethe 2." , ] ; Faroese: "Margreta 2." ; Greenlandic: "Margrethe II" ; full name: "Margrethe Alexandrine Þórhildur Ingrid"; born 16 April 1940) is the Queen of Denmark. She is also the supreme authority of the Church of Denmark and Commander-in-Chief of the Danish Defence. Born into the House of Glücksburg, a royal house with origins in Northern Germany, she was the eldest child of Frederick IX of Denmark and Ingrid of Sweden. She succeeded her father upon his death on 14 January 1972, having had become heir presumptive to her father in 1953, when a constitutional amendment allowed women to inherit the throne. On her accession, Margrethe became the first female monarch of Denmark since Margaret I, ruler of the Scandinavian kingdoms in 1375–1412 during the Kalmar Union. In 1967, she married Henri de Laborde de Monpezat, with whom she has two sons: Crown Prince Frederik (born 1968) and Prince Joachim (born 1969). She has been on the Danish throne for 45 years, becoming the second-longest-reigning Danish monarch after her ancestor Christian IV.
Document 10: Juliana Maria of Brunswick-Wolfenbüttel: Juliana Maria of Brunswick-Wolfenbüttel-Bevern (Danish: "Juliane Marie"; 4 September 1729 – 10 October 1796) was queen of Denmark between 1752 and 1766, second consort of king Frederick V of Denmark and Norway, mother of the prince-regent Hereditary Prince Frederick of Denmark and Norway and herself de facto regent 1772–1784. King Christian VIII of Denmark descends from her.
Document 11: Princess Margaretha, Mrs. Ambler: Princess Margaretha, Mrs. Ambler, (Margaretha Désirée Victoria; born 31 October 1934) is a Swedish princess, the eldest sister of King Carl XVI Gustaf of Sweden and also first cousin of Queen Margrethe II of Denmark.
Document 12: Ingrid of Sweden: Ingrid of Sweden (Ingrid Victoria Sofia Louise Margareta; 28 March 1910 – 7 November 2000) was Queen of Denmark from 1947 until 1972 as the wife of King Frederick IX.
Document 13: List of Swedish consorts: This is a list of Swedish queens consort and spouses of Swedish monarchs and regents. The list covers a large time span and the role of a consort has changed much over the centuries. The first Swedish consorts are spoken of in legends. The consorts until c. 1000 are often semi-legendary, as are the monarchs. Between the 14th and 16th century, during periods of de facto Swedish independence from the formal union with Denmark, the Swedish regents did not have the title of king or queen, nor did the spouses of kings have the title of queen consort, although they had the equivalent position. Due to unions with Finland, Denmark and Norway, many of the Swedish consorts were also consorts of monarchs of these countries. Consorts listed during the period of 1380–1520 were in fact also consorts to monarchs of Denmark. The consorts listed during the period of 1814-1905 were also consorts to monarchs of Norway. Finland was from the Middle Ages a part of Sweden, and although there was no official title, such as "Queen Consort of Finland", from the 16th century until the year of 1809, the queen consort of Sweden also held the title "Grand Princess of Finland."
Document 14: Prince Carl Bernadotte: Carl Gustaf Oscar Fredrik Christian, Prince Bernadotte (10 January 1911 – 27 June 2003), originally Prince Carl, Duke of Östergötland, was the youngest child and only son of Prince Carl of Sweden and Princess Ingeborg of Denmark and eventually a prince of the Belgian nobility. To distinguish himself from his father, he was widely known as "Carl Junior." He was the brother of Princess Margaretha of Sweden, Queen Astrid of Belgium and Crown Princess Märtha of Norway.
Document 15: Frederik, Crown Prince of Denmark: Frederik, Crown Prince of Denmark, Count of Monpezat, {'1': ", '2': ", '3': 'RE, SKmd', '4': "} (Frederik André Henrik Christian; born 26 May 1968) is the heir apparent to the throne of Denmark. Frederik is the elder son of Queen Margrethe II and Henrik, the Prince Consort.
ground_truth: 1947 until 1972