GDP is the total value of goods and services produced in a country in a year. It is calculated by adding consumption (C), investment (I), government spending (G), and net exports (X-M). Consumption makes up 66% of GDP and includes household spending on goods and services. Government spending makes up 25-35% and includes spending on military, education, and healthcare. Investment is business spending on capital goods like factories and equipment, making up 12-14% of GDP. The GPI is an alternative measure that adjusts GDP to account for economic factors not captured by GDP, such as the value of non-market work and costs of pollution.