Websites can easily sell for two times yearly earnings. Based on the earnings you report here, you could sell your site for around $200K without much hassle.
If you have a good business model, a long history of revenue, good relations with Google (no penalty history, no spammy tactics that are likely to get you penalized), and constantly increasing revenues, then your website could be worth up to ten times yearly earnings. So up to $1M in your case. Selling your website for that much takes a lot more work and luck on your part to find the interested buyer.
Interested buyers are going to want to see at least the following data:
- Earnings history
- Expense history (hosting, marketing, and other costs)
- How much time/effort it takes to keep the site running
- Traffic history
- Traffic sources
- Number of registered users
- Which SEO firms you have hired, or what SEO you have done on your own
- What technologies you use, and what their licenses are
- List of competitors
- List of anything that could be risky for your business