Guests came from more than 57,000 cities and 150 different countries to spend the night in interesting accommodations for the season – including tree houses, yurts, castles and a private island in Nicaragua. More than half of the guests this last year were women (54% female, 46% male), and the average traveler’s age was 35 years old, according to the report. Airbnb also claims to be helping the middle-class family supplement their income through the site. An earlier study conducted by former White House national economic advisor Gene Sperling found that the majority of hosts are working-class families who rent out their primary residence for about 66 days a year. According to that study, the average host also earned approximately $7,350, or a 14 percent raise in annual income from temporarily renting out their extra space. Get the full story at TechCrunch