Miami:

Tourism is also an important industry in Miami. Along with finance and business, the beaches, conventions, festivals and events draw over 38 million visitors annually into the city, from across the country and around the world, spending $17.1 billion. The Art Deco District in South Beach, is reputed as one of the most glamorous in the world for its nightclubs, beaches, historical buildings, and shopping. Annual events such as the Sony Ericsson Open, Art Basel, Winter Music Conference, South Beach Wine & Food Festival, and Mercedes-Benz Fashion Week Miami attract millions to the metropolis every year.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". How much money do tourists spend in Miami every month?
unanswerable