Regarding 200X pricing comparisons :
For years with rapid appreciation there can be a huge difference between the beginning of the year and the end. Prices were skyrocketing from 2003 to early 2005.
Take 2004 for example.
The County-wide median increased by about 22% from January 2004 to December 2004.
I think I could have sold my house in early 2004 for about 650-700K, but by the end of 2004 it would likely have sold for > 775K. I sold in mid-2005 for nearly 825K.