The World Bank Development Indicators

The World Bank was founded in 1944 with the goal of reducing poverty in the world. It contains five agencies and almost every country is a member of the World Bank. One of its functions is to keep track of the economic development of many countries. The World Development Indicators (WDI) is a collection of data for different countries over as long as possible. You can explore the database through their online interface.

This kind of development data can give great insights. You can find great examples of visualizations of development indicators at https://www.gapminder.org/tools/ like this one: