The United States is the world's third largest nation by total area (land and water), ranking behind Russia and Canada and just above China. With its large size and geographic variety, the United States includes most climate types.
The U.S. Census Bureau estimated the country's population to be 323,425,550 as of April 25, 2016, the third most populous nation in the world, after China and India.
The United States has a capitalist mixed economy which is fueled by abundant natural resources and high productivity. The nominal GDP of the U.S. is estimated to be $17.528 trillion as of 2014. The country ranks ninth in the world in nominal GDP per capita (first in the Americas) and sixth in GDP per capita at PPP. The U.S. dollar is the world's primary reserve currency. The U.S. economy is also the fastest growing in the Americas.
Chemical products are the leading manufacturing field. The United States is the largest producer of oil in the world, as well as its second-largest importer. It is the world's number one producer of electrical and nuclear energy, as well as liquid natural gas, sulfur, phosphates, and salt. The National Mining Association provides data pertaining to coal and minerals that include beryllium, copper, lead, magnesium, zinc, titanium and others.
The United States is also the world's top producer of corn and soybeans.
American public education is operated by state and local governments, regulated by the United States Department of Education through restrictions on federal grants. In most states, children are required to attend school from the age of six or seven (generally, kindergarten or first grade) until they turn 18 (generally bringing them through twelfth grade, the end of high school); some states allow students to leave school at 16 or 17.
The United States has many competitive private and public institutions of higher education. The majority of the world's top universities listed by different ranking organizations are in the U.S. There are also local community colleges with generally more open admission policies, shorter academic programs, and lower tuition.
American football is by several measures the most popular spectator sport; the National Football League (NFL) has the highest average attendance of any sports league in the world, and the Super Bowl is watched by millions globally. Baseball has been regarded as the U.S. national sport since the late 19th century, with Major League Baseball (MLB) being the top league. Basketball and ice hockey are the country's next two leading professional team sports, with the top leagues being the National Basketball Association (NBA) and the National Hockey League (NHL). These four major sports, when played professionally, each occupy a season at different, but overlapping, times of the year.
Health-care coverage in the United States is a combination of public and private efforts and is not universal. In 2014, 13.4% of the population did not carry health insurance. The subject of uninsured and underinsured Americans is a major political issue. In 2006, Massachusetts became the first state to mandate universal health insurance. Federal legislation passed in early 2010 would ostensibly create a near-universal health insurance system around the country by 2014, though the bill and its ultimate effect are issues of controversy.