Given the task definition and input, reply with output. This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.

Passage: After British imperial forces withdrew from most Canadian locations in 1870-71, the militia authorized the creation of two batteries of garrison artillery which provided garrison duties and schools of gunnery. "A " Battery School of Gunnery was established at Tête-de-Pont Barracks and other locations in Kingston . These batteries were known as the Regiment of Canadian Artillery.  When this regiment evolved into the Royal Canadian Horse Artillery , its headquarters was at the Tête-de-Pont Barracks from 1905 to 1939. After the RCHA left for operational duties during the Second World War, the fort was used as a personnel depot. In 1939 the site of the fort again became known as Fort Frontenac. Canadian Army staff training began at Fort Frontenac when the Canadian Army Staff College moved to the fort from the Royal Military College in 1948. The college is now known as the Canadian Army Command and Staff College. Fort Frontenac was also the location of the National Defence College until 1994. Fort Frontenac was designated a National Historic Site of Canada in 1923. 
Question: How many years after the Canadian Army Staff College move from the Royal Military College did  the National Defence College leave Fort Frontenac? 
Answer type: Number 

46.