Question: How much glaciation disappeared in the country where, along with Germany and the country where Monte Rosa Hotel is located, Lake Constance can be found?

full_context: Document 1: Rhine: Lake Constance consists of three bodies of water: the Obersee ("upper lake"), the Untersee ("lower lake"), and a connecting stretch of the Rhine, called the Seerhein ("Lake Rhine"). The lake is situated in Germany, Switzerland and Austria near the Alps. Specifically, its shorelines lie in the German states of Bavaria and Baden-Württemberg, the Austrian state of Vorarlberg, and the Swiss cantons of Thurgau and St. Gallen. The Rhine flows into it from the south following the Swiss-Austrian border. It is located at approximately 47°39′N 9°19′E﻿ / ﻿47.650°N 9.317°E﻿ / 47.650; 9.317.
Document 2: Alps: During the post-World War I period ski-lifts were built in Swiss and Austrian towns to accommodate winter visitors, but summer tourism continued to be important; by the mid-20th century the popularity of downhill skiing increased greatly as it became more accessible and in the 1970s several new villages were built in France devoted almost exclusively to skiing, such as Les Menuires. Until this point Austria and Switzerland had been the traditional and more popular destinations for winter sports, but by the end of the 20th century and into the early 21st century, France, Italy and the Tyrol began to see increases in winter visitors. From 1980 to the present, ski-lifts have been modernized and snow-making machines installed at many resorts, leading to concerns regarding the loss of traditional Alpine culture and questions regarding sustainable development as the winter ski industry continues to develop quickly and the number of summer tourists decline.
Document 3: 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 4: Rhine: The Rhine emerges from Lake Constance, flows generally westward, as the Hochrhein, passes the Rhine Falls, and is joined by its major tributary, the river Aare. The Aare more than doubles the Rhine's water discharge, to an average of nearly 1,000 m3/s (35,000 cu ft/s), and provides more than a fifth of the discharge at the Dutch border. The Aare also contains the waters from the 4,274 m (14,022 ft) summit of Finsteraarhorn, the highest point of the Rhine basin. The Rhine roughly forms the German-Swiss border from Lake Constance with the exceptions of the canton of Schaffhausen and parts of the cantons of Zürich and Basel-Stadt, until it turns north at the so-called Rhine knee at Basel, leaving Switzerland.
Document 5: 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 6: Rhine: The Rhine (Latin: Rhenus, Romansh: Rein, German: Rhein, French: le Rhin, Dutch: Rijn) is a European river that begins in the Swiss canton of Graubünden in the southeastern Swiss Alps, forms part of the Swiss - Liechtenstein, Swiss - Austrian, Swiss - German and then the Franco - German border, then flows through the German Rhineland and the Netherlands and eventually empties into the North Sea.
Document 7: 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 8: Alps: The region is serviced by 4,200 km (2,600 mi) of roads used by 6 million vehicles. Train travel is well established in the Alps, with, for instance 120 km (75 mi) of track for every 1,000 km2 (390 sq mi) in a country such as Switzerland. Most of Europe's highest railways are located there. Moreover, plans are underway to build a 57 km (35 mi)-long sub-alpine tunnel connecting the older Lötschberg and Gotthard tunnels built in the 19th century.
Document 9: 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 10: Monte Rosa Hotel: The Monte Rosa is a hotel, located in the main street of Zermatt. It was frequented by the members of the Alpine Club, including Edward Whymper who made the first ascent of the Matterhorn in 1865. The hotel is named after the highest mountain near Zermatt, Monte Rosa.
Document 11: Alps: Some high mountain villages, such as Avoriaz (in France), Wengen, and Zermatt (in Switzerland) are accessible only by cable car or cog-rail trains, and are car free. Other villages in the Alps are considering becoming car free zones or limiting the number of cars for reasons of sustainability of the fragile Alpine terrain.
Document 12: Matterhorn: The Matterhorn (German: Matterhorn, (ˈmatərˌhɔrn); Italian: Cervino, (ˈtʃerˈviːno); French: Le Cervin, (mɔ̃ sɛʁvɛ̃)) is a mountain of the Alps, straddling the main watershed and border between Switzerland and Italy. It is a large, near - symmetrical pyramidal peak in the extended Monte Rosa area of the Pennine Alps, whose summit is 4,478 metres (14,692 ft) high, making it one of the highest summits in the Alps and Europe. The four steep faces, rising above the surrounding glaciers, face the four compass points and are split by the Hörnli, Furggen, Leone, and Zmutt ridges. The mountain overlooks the Swiss town of Zermatt, in the canton of Valais, to the north - east and the Italian town of Breuil - Cervinia in the Aosta Valley to the south. Just east of the Matterhorn is Theodul Pass, the main passage between the two valleys on its north and south sides, and a trade route since the Roman Era.
Document 13: Gornergrat: The Gornergrat (; ) is a rocky ridge of the Pennine Alps, overlooking the Gorner Glacier south-east of Zermatt in Switzerland. It can be reached from Zermatt by the Gornergrat rack railway (GGB), the highest open-air railway in Europe. Between the Gornergrat railway station () and the summit is the Kulm Hotel () hosting the new Project "Stellarium Gornergrat" and until 2010 the "Kölner Observatorium für SubMillimeter Astronomie" KOSMA and before that (until 2005) the Gornergrat Infrared Telescope.
Document 14: Alps: The lower regions and larger towns of the Alps are well-served by motorways and main roads, but higher mountain passes and byroads, which are amongst the highest in Europe, can be treacherous even in summer due to steep slopes. Many passes are closed in winter. A multitude of airports around the Alps (and some within), as well as long-distance rail links from all neighbouring countries, afford large numbers of travellers easy access from abroad.
Document 15: Eiger: The first ascent was made by the western flank on August 11, 1858 by Charles Barrington with guides Christian Almer and Peter Bohren. They started at 3: 00 a.m. from Wengen. Barrington describes the route much as it is followed today, staying close to the edge of the north face much of the way. They reached the summit at about noon, stayed for some 10 minutes and descended in about four hours. Barrington describes the reaching of the top, saying, ``the two guides kindly gave me the place of first man up. ''Their ascent was confirmed by observation of a flag left on the summit. According to Harrer's The White Spider, Barrington was originally planning to make the first ascent of the Matterhorn, but his finances did not allow him to travel there as he was already staying in the Eiger region.
ground_truth: Forty percent
sub_queries: Monte Rosa Hotel >> located in the administrative territorial entity Answer: Zermatt
Where are the villages of Wengen and Zermatt located? Answer: Switzerland
Besides Germany and Switzerland , where else is Lake Constance? Answer: Austria
How much of the glaciation in Austria disappeared? Answer: Forty percent