Question: How much of the glaciation in the country where the Prinz Methusalem composer held citizenship has disappeared?

full_context: Document 1: Betulia liberata: The Mozart is the best known, if only because the composer's output receives more examination. Composed in March to July 1771 when Mozart was 15 years old, K. 118 (74c) is a 140-minute "azione sacra" on a text by Metastasio tracing the story of Judith and Holofernes from the biblical "". It was commissioned in March 1771 by Giuseppe Ximenes, Prince of Aragon, while Mozart and his father Leopold were on the way home to Salzburg from their first journey to Italy. It is the only oratorio Mozart ever wrote. Its two parts comprise sixteen arias, with solo or choral parts, scored for soloists, choir and orchestra. Not performed in Mozart's lifetime, "La Betulia liberata" is shaped stylistically to works by Leonardo Leo and Johann Adolph Hasse.
Document 2: Hérodiade: The libretto is a retelling of the story of John the Baptist, Salome, Herod Antipas and Herodias, but is strikingly less psychological and bloody than Richard Strauss's "Salome", which is based on a text by Oscar Wilde. The opera premiered in Brussels because Auguste Vaucorbeil, Manager of the Paris Opera house refused to stage the work; "I do like your music," he had said to Massenet, "but as for the libretto, you badly need an author who knows how to build the skeleton of a play."
Document 3: Johann Strauss III: Despite his keen interest in composing, he was better remembered as a conductor. His only stage work, the three-act operetta "Katze und Maus", composed in 1898, premiered in Vienna on 23 December 1898, at the Theater an der Wien. Its public reaction bordered on utter dislike, and music critics called for the distraught composer to reassess himself and to appear under a pseudonym, in order not to tarnish the name of his famous relatives. He salvaged the music score and produced independent pieces of which the waltzes "Sylvanien", Op. 1 and "Leonie", Op. 2 survived obscurity.
Document 4: Vienna Walzer Orchestra: The Vienna Walzer Orchestra (German: Wiener Walzer Orchester) is a chamber orchestra based in Vienna, Austria that specializes in traditional Viennese waltzes, polkas, marches and operetta arias from composers such as: J. Strauss II, F. Lehár, C.M. Ziehrer, among others. Their concerts also always include performances by ballet dancers and opera singers.
Document 5: Prinz Methusalem: Prinz Methusalem ("Prince Methusalem") is an operetta written by Johann Strauss II to a libretto by Karl Treumann, after Victor Wilder and Alfred Delacourt. It was first performed on January 3, 1877 in Vienna at the Carltheater. It achieved a run of eighty performances. The pot-pourri overture incorporates themes from the operetta, as well as other material that might have sometime been part of the planned score.
Document 6: Alps: The Alps provide lowland Europe with drinking water, irrigation, and hydroelectric power. Although the area is only about 11 percent of the surface area of Europe, the Alps provide up to 90 percent of water to lowland Europe, particularly to arid areas and during the summer months. Cities such as Milan depend on 80 percent of water from Alpine runoff. Water from the rivers is used in over 500 hydroelectricity power plants, generating as much as 2900 kilowatts of electricity.
Document 7: Alps: High levels of precipitation cause the glaciers to descend to permafrost levels in some areas whereas in other, more arid regions, glaciers remain above about the 3,500 m (11,483 ft) level. The 1,817 square kilometres (702 sq mi) of the Alps covered by glaciers in 1876 had shrunk to 1,342 km2 (518 sq mi) by 1973, resulting in decreased river run-off levels. Forty percent of the glaciation in Austria has disappeared since 1850, and 30% of that in Switzerland.
Document 8: Alps: Glaciers end in ice caves (the Rhone Glacier), by trailing into a lake or river, or by shedding snowmelt on a meadow. Sometimes a piece of glacier will detach or break resulting in flooding, property damage and loss of life. In the 17th century about 2500 people were killed by an avalanche in a village on the French-Italian border; in the 19th century 120 homes in a village near Zermatt were destroyed by an avalanche.
Document 9: Waltzes from Vienna: Waltzes from Vienna is a 1934 British musical film directed by Alfred Hitchcock, also known as Strauss' Great Waltz. It was part of the cycle of operetta films made in Britain during the 1930s.
Document 10: Hotel Sacher: The Hotel Sacher is a five-star hotel located in the Innere Stadt first district of Vienna, Austria, vis-à-vis to the Vienna State Opera. It is famous for the specialty of the house, the Sachertorte, a chocolate cake with apricot filling. There is also an art gallery in the hotel with works from the 19th century. The hotel is built near the former residence of Antonio Vivaldi.
Document 11: Alps: The Alps are a classic example of what happens when a temperate area at lower altitude gives way to higher-elevation terrain. Elevations around the world that have cold climates similar to those of the polar regions have been called Alpine. A rise from sea level into the upper regions of the atmosphere causes the temperature to decrease (see adiabatic lapse rate). The effect of mountain chains on prevailing winds is to carry warm air belonging to the lower region into an upper zone, where it expands in volume at the cost of a proportionate loss of temperature, often accompanied by precipitation in the form of snow or rain. The height of the Alps is sufficient to divide the weather patterns in Europe into a wet north and a dry south because moisture is sucked from the air as it flows over the high peaks.
Document 12: Der lustige Krieg: Der lustige Krieg ("The Merry War") is a three-act operetta composed by Johann Strauss II. The work was first performed on 25 November 1881 at the Theater an der Wien. Its libretto was by F Zell (Camillo Walzel) and Richard Genée. The operetta was well received at its premiere, and was performed 69 times during its first run.
Document 13: Switzerland: Switzerland lies between latitudes 45° and 48° N, and longitudes 5° and 11° E. It contains three basic topographical areas: the Swiss Alps to the south, the Swiss Plateau or Central Plateau, and the Jura mountains on the west. The Alps are a high mountain range running across the central-south of the country, comprising about 60% of the country's total area. The majority of the Swiss population live in the Swiss Plateau. Among the high valleys of the Swiss Alps many glaciers are found, totalling an area of 1,063 square kilometres (410 sq mi). From these originate the headwaters of several major rivers, such as the Rhine, Inn, Ticino and Rhône, which flow in the four cardinal directions into the whole of Europe. The hydrographic network includes several of the largest bodies of freshwater in Central and Western Europe, among which are included Lake Geneva (also called le Lac Léman in French), Lake Constance (known as Bodensee in German) and Lake Maggiore. Switzerland has more than 1500 lakes, and contains 6% of Europe's stock of fresh water. Lakes and glaciers cover about 6% of the national territory. The largest lake is Lake Geneva, in western Switzerland shared with France. The Rhône is both the main source and outflow of Lake Geneva. Lake Constance is the second largest Swiss lake and, like the Lake Geneva, an intermediate step by the Rhine at the border to Austria and Germany. While the Rhône flows into the Mediterranean Sea at the French Camarque region and the Rhine flows into the North Sea at Rotterdam in the Netherlands, about 1000 km apart, both springs are only about 22 km apart from each other in the Swiss Alps.
Document 14: Buckingham Palace: Before Prince Albert's death, the palace was frequently the scene of musical entertainments, and the greatest contemporary musicians entertained at Buckingham Palace. The composer Felix Mendelssohn is known to have played there on three occasions. Johann Strauss II and his orchestra played there when in England. Strauss's "Alice Polka" was first performed at the palace in 1849 in honour of the queen's daughter, Princess Alice. Under Victoria, Buckingham Palace was frequently the scene of lavish costume balls, in addition to the usual royal ceremonies, investitures and presentations.
Document 15: Classical period (music): However, Vienna's fall as the most important musical center for orchestral composition during the late 1820s, precipitated by the deaths of Beethoven and Schubert, marked the Classical style's final eclipse -- and the end of its continuous organic development of one composer learning in close proximity to others. Franz Liszt and Frédéric Chopin visited Vienna when they were young, but they then moved on to other cities. Composers such as Carl Czerny, while deeply influenced by Beethoven, also searched for new ideas and new forms to contain the larger world of musical expression and performance in which they lived.
ground_truth: Forty percent
sub_queries: Prinz Methusalem >> composer Answer: Johann Strauss II
Johann Strauss II >> country of citizenship Answer: Austria
How much of the glaciation in Austria disappeared? Answer: Forty percent