Query: How many tourists visited NYC in 2013?
Context: Tourism is a vital industry for New York City, which has witnessed a growing combined volume of international and domestic tourists – receiving approximately 51 million tourists in 2011, 54 million in 2013, and a record 56.4 million in 2014. Tourism generated an all-time high US$61.3 billion in overall economic impact for New York City in 2014.