The document categorizes countries into 8 groups based on population, capital city, and GDP per capita. It provides statistics for a total of 28 countries, with populations ranging from over 300 million (USA) to under 3 million (Uruguay). The countries fall into high-income countries (HIC), middle-income countries (MIC), and low-income countries (LIC) based on GDP per capita, with most having GDPs between $1000-40,000.