In countries with relatively low income inequality (e.g. the Slovak Republic), the gap between the mean and median income is small:
Look more to the south, and the difference between the mean and median income in Italy is almost 200 dollars (per month):
In the United States, the difference is about 500 dollars in monthly terms (~6000 dollars, annualized):
Median income in 2015 is extrapolated, but it is estimated to be still below its 2006 level...
The UK is interesting, as it seems to be a case where the gap between these summary statistics has shrunk:
All data were generated via http://gcip.info/graphs/