Depends on the employee's performance and value to the business.
I figure a decent employee who does his job but not to a level of excellence should get about a 3 or 4% year end bonus.
An exceptional employee who would seriously hurt the company if he left should get closer to 10%.
An employee who barely gets by but does not meet expectations should not get a bonus at all. In fact they shouldn't be employed there.
All bonus's should reflect personal performance, as well as the performance of the company. If the company is losing money, no bonus.
last year my potential bonus range was listed from zero to 10%. I got 12%. I had only been there 9 months but they figured out that I hired in cheap (even though I negotiated other things besides wages, like 4 weeks vacation to start) and I had mentioned that I only worked there because I wanted to keep busy, not because I needed the work or money. They justified the extra bonus money as "compensation compensation". I kid you not.
We don't get our bonus at the end of the year tho, we have to wait until the middle of March.
It'll be interesting to see what if anything I get this time