MOCAŠ
MB Enthusiast
Rather like house price values, this figure demonstrates how meaningless "average" figures can be when applied nationally.
"Meaningless" is something of an overstatement. There will, of course, be regional variations (and regional statistics for house prices/salaries/etc are readily available), but when looking at a trend over time, an average figure serves a valid purpose. You just need to adjust it to reflect individual (or local) circumstances.