Percentile rank is a linear distribution but income is not. A 95th percentile family has more in common, lifestyle wise, with a family 45 rank positions below it, than with a family 4.5 rank positions above it. A worker in the 95th percentile likely cannot quit his/her daytime job.
This is a 2011 income distribution graph. But the shape of the graph is still relevant.
http://www.npr.org/news/graphics/2011/05/gr-pm-income-brackets-462.gif
