Question: How many copies of the books by the author of The Leopard have sold worldwide?

full_context: Document 1: Phantom (Nesbø novel): Phantom is a crime novel by Norwegian novelist Jo Nesbø, published jn 2012. Its Norwegian title is "Gjenferd", which does not directly translate to "Phantom"; rather it translates to a word similar to "ghosts". "Phantom" is the ninth novel featuring crime detective Inspector Harry Hole.
Document 2: Harry Hole: Harry Hole (pronounced "Harry HOO-LEH") is the main character in a series of crime novels written by Norwegian author Jo Nesbø. Hole is a brilliant and driven detective with unorthodox methods, a classic loose cannon in the police force. Critics liken the personality of Harry Hole to those of the famous literary detectives: Sherlock Holmes, Hercule Poirot, Jules Maigret, and Nero Wolfe.
Document 3: The Leopard: The Leopard (Italian: "Il Gattopardo" ] ) is a novel by Giuseppe Tomasi di Lampedusa that chronicles the changes in Sicilian life and society during the "Risorgimento". Published posthumously in 1958 by Feltrinelli, after two rejections by the leading Italian publishing houses Mondadori and Einaudi, it became the top-selling novel in Italian history and is considered one of the most important novels in modern Italian literature. In 1959, it won Italy's highest award for fiction, the Strega Prize. In 2012, "The Observer" named it as one of "the 10 best historical novels". The novel was also made into an award-winning 1963 film of the same name, directed by Luchino Visconti and starring Burt Lancaster, Claudia Cardinale and Alain Delon.
Document 4: The Leopard (1963 film): The Leopard (Italian: "Il Gattopardo" , "The Serval"; alternative title: "Le Guépard") is a 1963 Italian epic period drama film by director Luchino Visconti, based on Giuseppe Tomasi di Lampedusa's novel of the same name.
Document 5: Skattejakten (novel): Skattejakten (in English "The Treasure Hunt"; this novel has been translated into English) is a Norwegian novel containing clues to a real-world treasure hunt. It is written by the author Margit Sandemo. The novel is only 124 pages long, and is possibly the shortest book the author has written. Skattejakten has not been reprinted after it was first published in 1999.
Document 6: The Black Box (novel): The Black Box is the 25th novel by American crime author Michael Connelly, and the sixteenth novel featuring Los Angeles Police Department detective Harry Bosch. The book was published on 26 November 2012, "in part to honor the 20th anniversary of the character".
Document 7: The Leopard (Nesbø novel): The Leopard is a crime novel by Norwegian novelist, Jo Nesbø. Its Norwegian title is "Panserhjerte", which does not directly translate to The Leopard; it rather means something along the lines of "armoured heart". Moreover, "leopard" refers to the stealthy tread of the killer in the book, while "armoured heart" is what Harry Hole himself gains by his experiences. "Panserhjerte" is also a Norwegian term for Constrictive pericarditis. "The Leopard" is the eighth novel featuring Nesbø's crime detective, Inspector Harry Hole.
Document 8: Restaurant Schrøder: Restaurant Schrøder is a restaurant in Waldemar Thranes gate 8 at St. Hanshaugen in Oslo, Norway. This restaurant appeared in several fictional works including Jo Nesbø's books about Harry Hole and several books by Bjørg Vik.
Document 9: The Panther (novel): The Panther is a 2012 novel by American author Nelson DeMille. It is the sixth of DeMille's novels to feature Detective John Corey, now working as a contractor for the fictional FBI Anti-Terrorist Task Force in New York City. The novel is the sequel to "The Lion". The Panther is followed by DeMille’s 2015 novel, "Radiant Angel". Also featured in this novel is DeMille’s other fictional character, Paul Brenner, who appears in The General's Daughter and Up Country.
Document 10: Police (Nesbø novel): Police (Norwegian: "Politi" , 2013) is a crime novel by Norwegian novelist Jo Nesbø. It is the tenth novel in Nesbø's Harry Hole series.
Document 11: The Son (Nesbø novel): The Son (Norwegian: "Sønnen" , 2014) is a crime novel by Norwegian novelist Jo Nesbø. It is the second stand-alone crime novel by Nesbø, following "Headhunters" (2008).
Document 12: Harry Bosch: Detective Hieronymus 'Harry' Bosch (pronounced "He-ron-ee-mus" "Bosh") is a Fictional character created by American author Michael Connelly. Bosch debuted as the lead character in the 1992 novel "The Black Echo", the first in a best-selling police procedural series now numbering twenty-one novels.
Document 13: Headhunters (film): Headhunters (Norwegian: "Hodejegerne" ) is a 2011 Norwegian action thriller film, based on the 2008 novel of the same name by Jo Nesbø. The film was directed by Morten Tyldum and stars Aksel Hennie, Nikolaj Coster-Waldau and Synnøve Macody Lund. Hennie portrays the successful but insecure corporate recruiter Roger Brown who lives a double life as an art thief to fund his lavish lifestyle. He finds out that one of his job prospects is in possession of a valuable painting and sets out to steal it.
Document 14: Jo Nesbø: Jo Nesbø (] ; born 29 March 1960) is a Norwegian writer, musician, former economist and reporter. As of March 2014 more than 3 million copies of his novels have been sold in Norway, and his work has been translated into over 40 languages, selling 30 million copies worldwide. Nesbø is primarily known for his crime novels about Inspector Harry Hole, but he is also the main vocalist and songwriter for the Norwegian rock band Di Derre. In 2007 Nesbø also released his first children's book, "Doktor Proktors Prompepulver" (English translation: "Doctor Proctor's Fart Powder"). The 2011 film "Headhunters" is based on Nesbø's novel "Hodejegerne (The Headhunters)".
Document 15: Shy Leopardess: Shy Leopardess is a fantasy novel by Leslie Barringer, the third and last book in his three volume Neustrian Cycle. It is set around the 14th century in an alternate medieval France called Neustria (historically an early division of the Frankish kingdom). The book was first published in the United Kingdom by Methuen in 1948. Its significance was recognized by its republication in the United States by the Newcastle Publishing Company as the thirteenth volume of the celebrated Newcastle Forgotten Fantasy Library series in October, 1977. The Newcastle edition was reprinted by Borgo Press in 1980.
ground_truth: 30 million