The United Kingdom (estimated 2010 GDP of $2.3 trillion) has the sixth-largest economy in the world, the third-largest economy in the European Union, and is a major international trading power. Highly developed, sophisticated, and diversified, the UK market is the largest in Europe and the fifth largest in the world for U.S. goods exports. With few barriers, the UK is the entry market into the EU for more than 40,000 U.S. exporters. The UK is the single largest export market for U.S. services exports. Annual U.S. exports of both goods and services are valued at more than $100 billion. Major categories of U.S. exports include aerospace, automotive, electronics, healthcare, information technologies, telecommunications, and safety/security equipment. The UK is the number one overseas market for travel to the United States, and nearly 4 million UK travelers visited the United States in 2010. The U.S.-UK investment relationship is largest in the world with a cumulative bilateral stock in direct investment valued over $925 billion. Over two million jobs, about one million in each country, have been created over the years to manage and drive this investment. Over 7,500 U.S. firms are present in the UK, and the UK is the top location in Europe for U.S. regional headquarters covering Europe, the Middle East, and Africa. London is a major international transportation and financial hub.