The Central Bank of Liberia is responsible for printing and maintaining the Liberian dollar, Liberia's primary currency. Liberia is one of the world's poorest countries, with a formal employment rate of 15%. GDP per capita peaked in 1980 at US$496, when it was comparable to Egypt's (at the time). In 2011 the country's nominal GDP was US$1.154 billion, while nominal GDP per capita stood at US$297, the third-lowest in the world. Historically the Liberian economy has depended heavily on foreign aid, foreign direct investment and exports of natural resources such as iron ore, rubber, and timber.