Question: When did Christopher Grotheer's sport get added to the Olympics?

full_context: Document 1: Frank Kleber: Frank Kleber (born 11 February 1981 in Gräfelfing) is a German skeleton racer who has competed since 2000. He won two medals at the FIBT World Championships with a gold in 2007 (Mixed team) and a bronze in 2004 (Men's skeleton).
Document 2: List of Olympic medalists in snowboarding: Snowboarding is a sport that has been contested at the Winter Olympic Games since the 1998 Winter Olympics in Nagano, Japan. Snowboarding was one of five new sports or disciplines added to the Winter Olympic programme between 1990 and 2002, and was the only one not to have been a previous medal or demonstration event. In 1998, four events, two for men and two for women, were held in two specialities: the giant slalom, a downhill event similar to giant slalom skiing; and the half - pipe, in which competitors perform tricks while going from one side of a semi-circular ditch to the other. Canadian Ross Rebagliati won the men's giant slalom and became the first athlete to win a gold medal in snowboarding. Rebagliati was briefly stripped of his medal by the International Olympic Committee (IOC) after testing positive for marijuana. However, the IOC's decision was reverted following an appeal from the Canadian Olympic Association. For the 2002 Winter Olympics, the giant slalom was dropped in favour of the parallel giant slalom, an event that involves head - to - head racing. In 2006, a third event, the snowboard cross, was held for the first time. In this event, competitors race against each other down a course with jumps, beams and other obstacles.
Document 3: Matthias Guggenberger: Matthias Guggenberger (born 24 September 1984 in Innsbruck) is an Austrian skeleton racer who has competed since 2005. His best Skeleton World Cup finish was 3rd at Königssee
Document 4: Short track speed skating at the Winter Olympics: Short track speed skating has been a contest at the Winter Olympics since the 1992 Winter Games in Albertville, France. Prior to that, it was a demonstration sport at the 1988 games. The results from the 1988 demonstration competition is not included in the official Olympic statistics. The sport has been dominated by teams from Asia and North America, namely South Korea (IOC code KOR), China (CHN), Canada (CAN) and the United States (USA). Those four countries have won 134 of 168 medals awarded since 1992. South Korea leads the medal tally (and gold medal tally), with 42 medals including 21 golds since 1992. The majority of medals that South Korea won at the Winter Olympics came from short - track speed skating. Similarly, most of the China's Winter Olympics medals are from the sport.
Document 5: Christopher Grotheer: Christopher Grotheer (born 30 July 1992) is a German skeleton racer who has competed since 2007. His debut at the European Cup was in November 2010. Grotheer's best Skeleton World Cup finish was 3rd in season 2012–13.
Document 6: Sandro Stielicke: Sandro Stielicke (born November 30, 1986 in Rostock) is a German skeleton racer who has competed since 2005. His best World Cup finish was third at Altenberg, Germany in December 2008.
Document 7: Julia Eichhorn: Julia Eichhorn (born July 11, 1983) is a German skeleton racer who has competed since 1999. Her best Skeleton World Cup finish was fifth at Königssee in February 2007.
Document 8: Luge: The first organized meeting of the sport took place in 1883 in Switzerland. In 1913, the Internationale Schlittensportverband or International Sled Sports Federation was founded in Dresden, Germany. This body governed the sport until 1935, when it was incorporated in the Fédération Internationale de Bobsleigh et de Tobogganing (FIBT, International Bobsleigh and Tobogganing Federation). After it had been decided that luge would replace the sport of skeleton at the Olympic Games, the first World Championships in the sport were held in 1955 in Oslo (Norway). In 1957, the Fédération Internationale de Luge de Course (FIL, International Luge Federation) was founded. Luge events were first included in the Olympic Winter Games in 1964.
Document 9: Gregor Stähli: Gregor Stähli (born 28 February 1968 in Zürich) is a Swiss skeleton racer who has competed since 1989. He won two bronze Winter Olympic medals in the men's skeleton, earning them in 2002 and 2006.
Document 10: Kerstin Szymkowiak: Kerstin Szymkowiak (born Kerstin Jürgens on 19 December 1977 in Siegen) is a German retired skeleton racer who has competed since 2002. She won three bronze medals in the women's skeleton event, earning them in 2004, 2008, and 2009.
Document 11: Figure skating at the Olympic Games: Figure skating was first contested in the Olympic Games at the 1908 Summer Olympics. Since 1924, the sport has been a part of the Winter Olympic Games.
Document 12: Snowboarding at the Winter Olympics: Snowboarding is a sport at the Winter Olympic Games. It was first included in the 1998 Winter Olympics in Nagano, Japan. Snowboarding was one of five new sports or disciplines added to the Winter Olympic program between 1992 and 2002, and was the only one not to have been a previous medal or demonstration event. In 1998, four events, two for men and two for women, were held in two specialities: the giant slalom, a downhill event similar to giant slalom skiing; and the half - pipe, in which competitors perform tricks while going from one side of a semi-circular ditch to the other. Canadian Ross Rebagliati won the men's giant slalom and became the first athlete to win a gold medal in snowboarding. Rebagliati was briefly stripped of his medal by the International Olympic Committee (IOC) after testing positive for marijuana. However, the IOC's decision was reverted following an appeal from the Canadian Olympic Association. For the 2002 Winter Olympics, giant slalom was expanded to add head - to - head racing and was renamed parallel giant slalom. In 2006, a third event, the snowboard cross, was held for the first time. In this event, competitors race against each other down a course with jumps, beams and other obstacles. On July 11, 2011, the International Olympic Committee's Executive Board approved the addition of Ski and Snowboard Slopestyle to the Winter Olympics roster of events, effective in 2014. The decision was announced via press conference from the IOC's meeting in Durban, South Africa. A fifth event, parallel slalom, was added only for 2014. Big air was added for 2018.
Document 13: Figure skating: Figure skating is a sport in which individuals, duos, or groups perform on figure skates on ice. It was the first winter sport included in the Olympics, in 1908. The four Olympic disciplines are men's singles, ladies' singles, pair skating, and ice dance. Non-Olympic disciplines include synchronized skating, Theater on Ice, and four skating. From novice through senior - level competition, skaters generally perform two programs (short and long) which, depending on the discipline, may include spins, jumps, moves in the field, lifts, throw jumps, death spirals, and other elements or moves.
Document 14: Chris Soule: Chris Soule (born February 5, 1973) is an American skeleton racer who competed from 1993 to 2006. He won two medals in the men's skeleton event at the FIBT World Championships with a silver in 2003 and a bronze in 1997. Soule also won the overall men's 20023 Skeleton World Cup title with multiple World Cup victories that season. He is the 3-time U.S. National Champion and remains one of the most decorated Skeleton athletes in the history of the sport.
Document 15: Skeleton at the Winter Olympics: Skeleton is a winter sport featured in the Winter Olympics where the competitor rides head - first and prone (lying face down) on a flat sled. It is normally run on an ice track that allows the sled to gain speed by gravity. It was first contested at the 1928 Winter Olympics in St. Moritz and again in 1948 Winter Olympics, after which it was discontinued as an Olympic sport. Skeleton was reintroduced at the 2002 Winter Olympics, with both men's and women's events, and has been held in each Winter Olympic competition since. Skeleton is so - named as the first metal sleds introduced in 1892 were said to resemble a human skeleton.
ground_truth: 1928
sub_queries: Christopher Grotheer >> sport Answer: skeleton
when did the skeleton become an olympic sport Answer: 1928