United States

In 1876, Alexander Graham Bell was awarded the first U.S. patent for the telephone. Thomas Edison's research laboratory, one of the first of its kind, developed the phonograph, the first long-lasting light bulb, and the first viable movie camera.[401] The latter led to emergence of the worldwide entertainment industry. In the early 20th century, the automobile companies of Ransom E. Olds and Henry Ford popularized the assembly line. The Wright brothers, in 1903, made the first sustained and controlled heavier-than-air powered flight.[402]

The rise of fascism and Nazism in the 1920s and 30s led many European scientists, including Albert Einstein, Enrico Fermi, and John von Neumann, to immigrate to the United States.[403] During World War II, the Manhattan Project developed nuclear weapons, ushering in the Atomic Age, while the Space Race produced rapid advances in rocketry, materials science, and aeronautics.[404][405]

The invention of the transistor in the 1950s, a key active component in practically all modern electronics, led to many technological developments and a significant expansion of the U.S. technology industry.[406] This, in turn, led to the establishment of many new technology companies and regions around the country such as Silicon Valley in California. Advancements by American microprocessor companies such as Advanced Micro Devices (AMD) and Intel, along with both computer software and hardware companies such as Adobe Systems, Apple Inc., IBM, Microsoft, and Sun Microsystems, created and popularized the personal computer. The ARPANET was developed in the 1960s to meet Defense Department requirements, and became the first of a series of networks which evolved into the Internet.[407]

Income, wealth, and poverty

Accounting for 4.24% of the global population, Americans collectively possess 29.4% of the world's total wealth, the largest percentage of any country.[408][409] The U.S. also ranks first in the number of billionaires and millionaires in the world, with 724 billionaires and 10.5 million millionaires as of 2020.[410][411] The Global Food Security Index ranked the U.S. number one for food affordability and overall food security in March 2013.[412] Americans on average have more than twice as much living space per dwelling and per person as EU residents.[413] For 2017 the United Nations Development Programme ranked the United States 13th among 189 countries in its Human Development Index (HDI) and 25th among 151 countries in its inequality-adjusted HDI (IHDI).[414]

Wealth, like income and taxes, is highly concentrated; the richest 10% of the adult population possess 72% of the country's household wealth, while the bottom half possess only 2%.[416] According to the Federal Reserve, the top 1% controlled 38.6% of the country's wealth in 2016.[417] In 2017, Forbes found that just three individuals (Jeff Bezos, Warren Buffett and Bill Gates) held more money than the bottom half of the population.[418] According to a 2018 study by the OECD, the United States has a larger percentage of low-income workers than almost any other developed nation, largely because of a weak collective bargaining system and lack of government support for at-risk workers.[419] The top one percent of income-earners accounted for 52 percent of the income gains from 2009 to 2015, where income is defined as market income excluding government transfers.[420]

After years of stagnation, median household income reached a record high in 2016 following two consecutive years of record growth. Income inequality remains at record highs however, with the top fifth of earners taking home more than half of all overall income.[421] The rise in the share of total annual income received by the top one percent, which has more than doubled from nine percent in 1976 to 20 percent in 2011, has significantly affected income inequality,[422] leaving the United States with one of the widest income distributions among OECD nations.[423] The extent and relevance of income inequality is a matter of debate.[424][425][426]

There were about 567,715 sheltered and unsheltered homeless persons in the U.S. in January 2019, with almost two-thirds staying in an emergency shelter or transitional housing program.[427] In 2011, 16.7 million children lived in food-insecure households, about 35% more than 2007 levels, though only 845,000 U.S. children (1.1%) saw reduced food intake or disrupted eating patterns at some point during the year, and most cases were not chronic.[428] As of June 2018[update], 40 million people, roughly 12.7% of the U.S. population, were living in poverty, including 13.3 million children. Of those impoverished, 18.5 million live in deep poverty (family income below one-half of the poverty threshold) and over five million live "in 'Third World' conditions".[429] In 2017, the U.S. states or territories with the lowest and highest poverty rates were New Hampshire (7.6%) and American Samoa (65%), respectively.[430][431][432] The economic impact and mass unemployment caused by the COVID-19 pandemic raised fears of a mass eviction crisis,[433] with an analysis by the Aspen Institute indicating that between 30 and 40 million people were at risk for eviction by the end of 2020.[434]

Transportation

Personal transportation is dominated by automobiles, which operate on a network of 4 million miles (6.4 million kilometers) of public roads.[436] The United States has the world's second-largest automobile market,[437] and has the highest vehicle ownership per capita in the world, with 816.4 vehicles per 1,000 Americans (2014).[438] In 2017, there were 255,009,283 non-two wheel motor vehicles, or about 910 vehicles per 1,000 people.[439]

The civil airline industry is entirely privately owned and has been largely deregulated since 1978, while most major airports are publicly owned.[440] The three largest airlines in the world by passengers carried are U.S.-based; American Airlines is number one after its 2013 acquisition by US Airways.[441] Of the world's 50 busiest passenger airports, 16 are in the United States, including the busiest, Hartsfield–Jackson Atlanta International Airport.[442]

The United States has the longest rail network in the world, nearly all standard gauge. The network handles mostly freight, with intercity passenger service provided by the government-subsidized Amtrak to all but four states.[443]

Transport is the largest single source of greenhouse gas emissions by the United States, which are the second highest by country, exceeded only by China's.[444] The United States has historically been the world's largest producer of greenhouse gases, and greenhouse gas emissions per capita remain high.[445]

Energy

The United States energy market is about 29,000 terawatt hours per year.[446] In 2018, 37% of this energy came from petroleum, 31% from natural gas, and 13% from coal. The remainder was supplied by nuclear and renewable energy sources.[447]