Knowing the average income per capita or the median income is a rather poor economical indicator of a country, even when given in PPP\$. Knowing the (dimension-less) Gini index is somehow better, but it's too abstract a quantity and doesn't - as a number - tell too much. The Lorenz curve from which the Gini index is derived contains a bit more information but it is still hard to grasp: "What exactly do these curves tell me?"
The most objective and intuitive way of displaying income statistics possibly is just plotting the number of people over income (blue) and the accumulated income per income group (silver):
Unfortunately I find such plots only rarely. What I am looking for is a database where I can find the appropriate data (e.g. relative sizes of 10 or 20 income groups) for ideally all countries of the world.
The World Bank seems to publish only income shares held by the kth 20% which is better than nothing and does allow to draw Lorenz curves. But it would not allow to draw more detailed income distributions.
Where do I find such data: number of capita per income (with appropriate income bins: < 10%, < 20%, .... > 90% of the average (or median) income).