Question: What year did Pietro Ferrero introduce his famous hazelnut cocoa product?

full_context: Document 1: Ferrero SpA: Ferrero SpA (] ) is an Italian manufacturer of branded chocolate and confectionery products and it is the third biggest chocolate producer and confectionery company in the world. It was founded in 1946 in Alba, Piedmont, Italy, by Pietro Ferrero, a confectioner and small-time pastry maker who laid the groundwork for Nutella and famously added hazelnut to save money on chocolate. The company saw a period of tremendous growth and success under Pietro's son Michele Ferrero, who in turn handed over the daily operations to his sons. His son Pietro (the founder's grandson), who oversaw global business, died on April 18, 2011, in a cycling accident in South Africa at the age of 47. The Ferrero Group worldwide – now headed by CEO Giovanni Ferrero – includes 38 trading companies, 18 factories, approximately 21,500 employees and produces around 365,000 tonnes of Nutella each year. Ferrero International SA's headquarters is in Luxembourg. Ferrero SpA is a private company owned by the Ferrero family and has been described as "one of the world's most secretive firms". Reputation Institute's 2009 survey ranks Ferrero as the most reputable company in the world. The recently announced financial results for the fiscal year ending August 31, 2016 showed consolidated sales growth of 8.2% from the previous fiscal year.
Document 2: Pietro Ferrero: Pietro Ferrero (2 September 1898 – 2 March 1949) was the founder of Ferrero SpA, an Italian confectionery and chocolatier company. His company invented Nutella, a hazelnut-cream spread, which is now sold in over 160 countries. The famous Ferrero Rochers are also made by his company, Ferrero, as were Tic-Tacs and various Kinder chocolates.
Document 3: Milka: Milka is a brand of chocolate confection which originated in Switzerland in 1901 and has been manufactured internationally by the US confectionery company Mondelēz International (formerly known as Kraft Foods) since 1990. For more than 100 years Milka has been primarily produced in Lörrach, Germany, producing about 140,000 tonnes of chocolate in 2012. It is sold in bars and a number of novelty shapes for Easter and Christmas. Milka also produces chocolate-covered cookies and biscuits.
Document 4: Nutella: Nutella ( ; ] ) is a brand of sweetened hazelnut cocoa spread manufactured by the Italian company Ferrero that was first introduced in 1965, although its first iteration dates to 1963.
Document 5: Squirrel nut caramel: Squirrel Nut Caramels (chocolate flavored) and Squirrel Nut Zippers (vanilla flavored) are chewy caramel candy mixed with peanuts.
Document 6: Cadbury: Cadbury, formerly Cadbury's, is a British multinational confectionery company wholly owned by Mondelez International (originally Kraft Foods) since 2010. It is the second-largest confectionery brand in the world after Wrigley's. Cadbury is internationally headquartered in Uxbridge, West London, and operates in more than 50 countries worldwide. It is famous for its Dairy Milk chocolate, the Creme Egg and Roses selection box, and many other confectionery products. One of the best-known British brands, in 2013 "The Daily Telegraph" named Cadbury among Britain's most successful exports.
Document 7: Forrest Mars Jr.: Forrest Edward Mars Jr. (August 16, 1931 – July 26, 2016) was an American heir. He was the eldest son of Audrey Ruth (Meyer) and Forrest Mars Sr., and the grandson of Frank C. Mars, the founder of Mars, Incorporated, the confectionery company. In March 2015, "Forbes" estimated his wealth to be $26.8 billion
Document 8: Mars, Incorporated: Mars is an American global manufacturer of confectionery, pet food, and other food products and a provider of animal care services, with US$33 billion in annual sales in 2015, and is ranked as the 6th largest privately held company in the United States by Forbes. Headquartered in McLean, unincorporated Fairfax County, Virginia, US, the company is entirely owned by the Mars family. Mars operates in six business segments around the world: Wm. Wrigley Jr. Company (Chicago, Illinois), Chocolate (Hackettstown, New Jersey; to be integrated with Wm. Wrigley Jr. Company and based in Chicago, Illinois from 2017), Petcare (Brussels, Belgium, Poncitlán and Jalisco, Mexico), Food (Rancho Dominguez, California), Drinks (West Chester, Pennsylvania), and Symbioscience (Germantown, Maryland), the company's life sciences division.
Document 9: Eskimo Pie: Eskimo Pie is a brand name for a chocolate-covered vanilla ice cream bar wrapped in foil, the first such dessert sold in the United States. It is now marketed by Nestlé, owners of Dreyer's of the Western United States, and Edy's of the Eastern United States. The product was introduced to New Zealand in the 1940s, and is produced by Tip Top who are now a subsidiary of Fonterra, the country's largest multinational company.
Document 10: Fun Dip: Fun Dip is a candy manufactured by The Willy Wonka Candy Company, a brand owned by Nestlé. The candy has been on the market in the United States and Canada since the 1940s and was originally called Lik-M-Aid. It was originally manufactured by Fruzola, and then Sunline Inc., through their Sunmark Brands division, which was purchased by Nestlé in January 1989. It comes in many different flavors with candy sticks that are included.
Document 11: Nestlé Bear Brand: Bear Brand is a powdered milk drink brand introduced in 1976, which was owned by Nestlé. It is available in most areas of Southeast Asia. Bear Brand is also marketed under the brand name Marca Oso, which is Spanish for "Bear Brand". The brand's Indonesian name is Susu Cap Beruang. Bear Brand is also a sterilized milk brand. In 2014, a consumer research firm ranked Bear Brand milk as No. 6 among the top 50 "most popular fast-moving consumer goods" in the Philippines.
Document 12: Pietro Ferrero Jr.: Pietro Ferrero (11 September 196318 April 2011) was the joint CEO (with his brother Giovanni) of Italian confectionery company Ferrero SpA, from 1997 until his death in April 2011.
Document 13: Hershey bar: The Hershey's Milk Chocolate Bar (commonly called the Hershey's Bar) is the flagship chocolate bar manufactured by the Hershey Company. It is often referred by Hershey as "The Great American Chocolate Bar." The Hershey Milk Chocolate Bar was first sold in 1900, followed by the Hershey's Milk Chocolate with Almonds variety, which began production in 1908.
Document 14: Giovanni Ferrero: Giovanni Ferrero (born 21 September 1964) is an Italian businessman. He assumed the leadership of the confectionery company Ferrero SpA after the death of his brother Pietro Ferrero in 2011. He has a net worth of $24.2 billion as of May 2016, according to Bloomberg.
Document 15: Ferrero-Küsschen: Ferrero Küsschen (meaning little kisses) are Ferrero company chocolates that consist of a whole roasted hazelnut filled with hazelnut cream including vegetable oil and covered in milk chocolate.
ground_truth: 1965