Question: Which year witnessed the formation of the publisher of Sisters?

full_context: Document 1: Toxic Bachelors: Toxic Bachelors is a novel by Danielle Steel, published by Random House in October 2005. The book is Steel's sixty-seventh novel.
Document 2: Miracle (novel): Miracle is a novel written by Danielle Steel and published by Random House in June 2005. The book is Steel's sixty-sixth novel.
Document 3: Forever in Blue: The Fourth Summer of the Sisterhood: Forever in Blue: The Fourth Summer of the Sisterhood (also known as Forever in Blue) is the fourth novel in Ann Brashares's acclaimed "Sisterhood" series. The story concludes the adventures of four girls who share a pair of "magical" pants that fit each one of them perfectly, despite their vastly different shapes and sizes. This is the fourth book in "The Sisterhood of the Traveling Pants" series and was considered the last until Brashares published a fifth book in 2011. It was released on January 9, 2007.
Document 4: Miami: Several large companies are headquartered in or around Miami, including but not limited to: Akerman Senterfitt, Alienware, Arquitectonica, Arrow Air, Bacardi, Benihana, Brightstar Corporation, Burger King, Celebrity Cruises, Carnival Corporation, Carnival Cruise Lines, Crispin Porter + Bogusky, Duany Plater-Zyberk & Company, Espírito Santo Financial Group, Fizber.com, Greenberg Traurig, Holland & Knight, Inktel Direct, Interval International, Lennar, Navarro Discount Pharmacies, Norwegian Cruise Lines, Oceania Cruises, Perry Ellis International, RCTV International, Royal Caribbean Cruise Lines, Ryder Systems, Seabourn Cruise Line, Sedano's, Telefónica USA, UniMÁS, Telemundo, Univision, U.S. Century Bank, Vector Group and World Fuel Services. Because of its proximity to Latin America, Miami serves as the headquarters of Latin American operations for more than 1400 multinational corporations, including AIG, American Airlines, Cisco, Disney, Exxon, FedEx, Kraft Foods, LEO Pharma Americas, Microsoft, Yahoo, Oracle, SBC Communications, Sony, Symantec, Visa International, and Wal-Mart.
Document 5: Random House: Penguin Random House Grupo Editorial is Random House's Spanish-language division, targeting markets in Spain and South and Central America. It is headquartered in Barcelona with locations in Argentina, Chile, Colombia, Mexico, Uruguay, and the United States. From 2001 until November 2012, it was a joint venture with Italian publisher Mondadori (Random House Mondadori). Upon Bertelsmann's acquisition of Mondadori's stake in the JV, the name was kept temporarily four months. Some authors published by Penguin Random House Grupo Editorial include Dr. César Lozano, Yordi Rosado, Dr. Nancy Alvarez and Alberto Sardiñas.
Document 6: Bantam Books: Bantam Books is an American publishing house owned entirely by parent company Random House, a subsidiary of Penguin Random House; it is an imprint of the Random House Publishing Group. It was formed in 1945 by Walter B. Pitkin, Jr., Sidney B. Kramer, and Ian and Betty Ballantine, with funding from Grosset & Dunlap and Curtis Publishing Company. It has since been purchased several times by companies including National General, Carl Lindner's American Financial and, most recently, Bertelsmann; it became part of Random House in 1998, when Bertelsmann purchased it to form Bantam Doubleday Dell. It began as a mass market publisher, mostly of reprints of hardcover books, with some original paperbacks as well. It expanded into both trade paperback and hardcover books, including original works, often reprinted in house as mass-market editions.
Document 7: Boston: The city's growing Latino population has given rise to a number of local and regional Spanish-language newspapers. These include El Planeta (owned by the former publisher of The Boston Phoenix), El Mundo, and La Semana. Siglo21, with its main offices in nearby Lawrence, is also widely distributed.
Document 8: Cemex: Lorenzo Zambrano was the chairman and chief executive officer until his death on May 21, 2014. About one-third of the company's sales come from its Mexico operations, a quarter from its plants in the U.S., 15% from Spain, and smaller percentages from its plants around the world.
Document 9: Bungalow 2: Bungalow 2 is a novel by Danielle Steel, published by Random House in June 2007. The book is Steel's seventy-second novel.
Document 10: Department store: The first department store in Spain was Almacenes el Siglo opened in October 1881 in Barcelona. Following the 2002 closure by the Australian group Partridges of their SEPU (Sociedad Española de Precios Unicos) department store chain, which was one of Spain's oldest, the market is now dominated by El Corte Inglés, founded in 1934 as a drapery store. El Corte Inglés stores tend to be vast buildings, selling a very broad range of products and the group also controls a number of other retail formats including supermarket chain 'Supercor' and hypermarket chain 'Hipercor'. Other competitors such as 'Simago' and 'Galerías Preciados' closed in the 1990s, however El Corte Inglés, faces major competition from French discount operators such as Carrefour and Auchan.
Document 11: P.S. I Still Love You: P.S. I Still Love You Author Jenny Han Country United States Language English Genre Young adult Publisher Simon & Schuster Publication date May 26, 2015 Media type Print (hardback, paperback) Pages 337 ISBN 978 - 1442426740 Preceded by To All the Boys I've Loved Before Followed by Always and Forever, Lara Jean
Document 12: Indiana Jones and the Seven Veils: Indiana Jones and the Seven Veils is the third of 12 Indiana Jones novels published by Bantam Books. Rob MacGregor, the author of this book, also wrote five of the other Indiana Jones books for Bantam. Published on November 1, 1991, it is preceded by "Indiana Jones and the Dance of the Giants" and followed by "Indiana Jones and the Genesis Deluge".
Document 13: Sisters (Steel novel): Sisters is a novel by Danielle Steel, published by Random House in February 2007. The book is Steel's seventy-first novel.
Document 14: Eduardo Mendoza Garriga: Eduardo Mendoza Garriga (born 11 January 1943 in Barcelona, Spain) is a Spanish novelist. He studied law in the first half of the 1960s and lived in New York City between 1973 and 1982, working as interpreter for the United Nations, and then tried to become a lawyer and then he realized that he wanted to be a writer. He maintained an intense relationship with novelists Juan Benet and Juan García Hortelano, poet Pere Gimferrer and writer (and neighbour) Félix de Azúa. He currently lives in London.
Document 15: Belén Gache: Of Spanish and Gibraltarian descent, she was born in Buenos Aires. She lives in Madrid. She graduated from the University of Buenos Aires where she was professor in narratology and literary theory. Her work has diversified into different literary forms. Departing from narrative, she became a pioneer of electronic literature producing since 1996 various forms of expanded and hypertextual writings.
ground_truth: 2001
sub_queries: Sisters >> publisher Answer: Random House
Which year witnessed the formation of Random House ? Answer: 2001