I'm not even sure how many I get per year, but they carry over from year to year. I was able to use some of my accumulated sick days to care for my Mom (I think it's up to 5 per year).
But I rarely take a sick day, mainly because I work half-days and seriously, with a 15 minute commute, I can handle a short day, then go home and collapse! (I also work alone, with people stopping by my office, so I don't have to be too concerned about infecting anyone else.)