A billionaire is a person with a net worth of at least one billion units of a given currency, usually of a major currency such as the United States dollar, euro, or pound sterling. The American business magazine Forbes produces a global list of known U.S. dollar billionaires every year and updates an Internet version of this list in real time. The American oil magnate John D. Rockefeller became the world's first confirmed U.S. dollar billionaire in 1916. As of 2018, there are over 2,200 U.S. dollar billionaires worldwide, with a combined wealth of over US$ 9.1 trillion, up from US$7.67 trillion in 2017. According to a 2017 Oxfam report, the top eight richest billionaires own as much combined wealth as "half the human race". As of 2021, eight people have reached the status of USD hectobillionaires, meaning that each has had a net worth of at least $100 billion.