2008 was a record year when 47 million tourists visited the Big Apple. (The industry standard defines a visit by a tourist as a visit by someone who travels more than fifty miles--not including commuters--or spends one night in the city.) New York tourism in 2009 saw a predictable dip with the financial woes of the country and world, but still managed to attract 45.6 million.
2010 set a new record with 48.7 million visitors. 39 million were Americans and 9.7 million were from abroad. (A whopping 33% of international visitors came to New York. Miami and Los Angeles--tied for second--each attracted 11%.)
Tourism is now New York's fifth-largest industry, and 2010's banner year brought $31 billion in direct spending to our metropolis.