The legal minimum is 20 working days, though. The people in tech I've met in Berlin are getting anything between 26 and 30. My contract starts with 27 days and this number will be raised every year I'm working there till it reaches 30.
Legally is zero days in the US. I met people with 3-5 days per year. Most companies give you 10 days to start so that's considered standard. It took me 15 years to get to 20. There are some exceptions of course with a generous amount of days or unlimited vacation, but the vast mayority of corporations in the US go with 10,15,20 and maybe 25 once you spend 30+ years with the company.