In 2021, U.S. residents aged 15 and older spent an average of 0.7 hours per day shopping, 3.5 hours on work & education, and 5.3 hours on leisure & sports. The material living standards of nations are primarily driven by how much people work and how productively they do it. These factors form the very definition of economic output, or gross domestic product, which is equal to "hours worked times labor productivity." Total work hours and productivity tend to increase over time due to population growth and the advance of technology, but the rate of increase in the U.S. for the past two decades has been low compared to prior decades, and hence, so has economic growth. Many factors can affect work hours and productivity, but three of the most direct and drastically changing over recent decades are government debt, regulations, and social programs.