context: In 2013 the United States Patent & Trademark Office approximated that the worth of intellectual property to the U.S. economy is more than US$5 trillion and creates employment for an estimated 18 million American people. The value of intellectual property is considered similarly high in other developed nations, such as those in the European Union. In the UK, IP has become a recognised asset class for use in pension-led funding and other types of business finance. However, in 2013, the UK Intellectual Property Office stated: "There are millions of intangible business assets whose value is either not being leveraged at all, or only being leveraged inadvertently".
question: 2013లో ఎన్ని అమెరికన్లు మేధో సంపత్తి ద్వారా ఉపాధి పొందారు?
answers: 18 million