Hi @Alicia98
Airbnb has 2 milion plus listing all around the world, and every day is growing, in Sydney grow between 30 to 100 a day.
in 2015 were 8.000 listing in Sydney, today we are in 23.615
http://insideairbnb.com/sydney/?neighbourhood=&filterEntireHomes=false&filterHighlyAvailable=false&f...
Only in California there is 125.803 listing, San Francisco has 8.655 listing and is the city were Airbnb born, so don't be surprised. 🙂
http://insideairbnb.com/san-francisco/
Everytime a new listing is add, is override to the top, so someone else listing go to the bottom, you have to update and interact with your listing everyday if you want to stay at the top and get some booking.
some stats:
http://blog.airdna.co/2015-in-review-airbnb-data-for-the-usa/
Goodluck
Cheers Raf