Usually, relative poverty is measured as the percentage of the population with income less than some fixed proportion of median income. This is a calculation of the percentage of people whose family household income falls below the Poverty Line. The main poverty line used in the OECD and the European Union is based on "economic distance", a level of income set at 60% of the median household income. The United States federal government typically regulates this line to three times the cost an adequate meal.