Design choices
The design is intentionally abstract. We included no scale for time, share or income because we wanted the image to convey the general impression in a visually attractive way.
Using these simple stacked bar charts without representing the middle class, the readers can use their intuition that the richest quintile is at the top and the poorest at the bottom.
The panel chart allows to see several countries at once, rather than having to select countries with a drop down menu for instance.
A different colour, along with a white separator, is applied to each 20% share of income to clearly identify when the top quantile owns more than double or triple its proportional share of income.