This visualization is part of the OECD challenge to represent the data from their Return on education study.
The aim of this representation was to provide an overview of the very dense and rich data, collected in many different countries, showing how much money is invested in education, at different levels, either by individuals or by governments and what are the return of this investment.
Using different graphical reprensations, the goal is to encourage comparison of different levels of education in one country and between different countries.
The dollar sign is to be understood as US dollars, as in the original data set.