An annual bonus of 5-10% of your yearly salary is standard in a lot of industries, just as a 5-10% annual raise is considered standard. However, if you work on commission, you may see a significantly higher percentage. Your industry, company revenue, location, and level also heavily inform what's expected.
Most companies assign a target bonus that each employee is eligible to receive at the end of the year. The employer awards the full annual bonus if the employee meets specific goals and the company or department meets its performance goals.