Healthcare: This one has more to do with sheer population numbers in the Big Apple than any other inherently New York aspect of the economy. It only makes sense that the biggest city in the country will also have the biggest need for doctors, nurses, and other trained medical professions to address the issues of wellness, medical research, and pharmaceuticals. According to several studies, New York has more than 60,000 registered licensed physicians to its name, more recipients of post-graduate degrees in life science than any other American city, and one of the biggest bio-medical industries in the country.