The Geary–Khamis dollar, more commonly known as the international dollar, is a hypothetical unit of currency that has the same purchasing power parity that the U.S. dollar had in the United States at a given point in time. It is widely used in economics. The years 1990 or 2000 are often used as a benchmark year for comparisons that run through time. The unit is often abbreviated e.g. 2000 US dollar (if the benchmark year is 2000) or 2000 Int$.