New Delhi: The United State of America is the world's largest national economy, with an estimated 2013 GDP of $16.2 trillion –22% of global GDP at purchasing-power parity, as of 2011. It is the world's foremost economic and military power, a prominent political and cultural force, and a leader in scientific research and technological innovation.It is one of the world's most ethnically diverse and multicultural nations. Here are ten interesting facts to know about USA: Today, 66 percent of all Americans are considered to be overweight. Approximately 48 percent of all Americans are currently either considered to be "low income" or are living in poverty. The United States is divided into 50 states. However state each varies in size considerably. The smallest state is Rhode Island with an area of just 1,545 square miles (4,002 sq km). By contrast the largest state by area is Alaska with 663,268 square miles (1,717,854 sq km). The U.S. Constitution is widely considered to be the oldest constitution presently in existence. It has completed 226 years on 17th of September 2013. In the United States, an average of about $8,500 is spent on healthcare per person each year. The United States has 845 motor vehicles for every 1,000 people. According to the Federal Reserve Bank of New York, approximately 167,000 Americans have more than $200,000 of student loan debt. The United States has a teen pregnancy rate of 22 percent. The only place in the United States where coffee is grown commercially is in Hawaii. One survey found that 25 percent of all employees that have Internet access in the United States visit pornography websites while they are at work.