The currency in Iran, or the money used, is called the rial (pronounced ‘reeyaal’). The rial is like the dollar or a pound in that is made up of 100 pieces, in Iran called dinars. However, due to high inflation one riyal is worth so little that no fraction of it is really used on a day to day basis.
Iran's population increased dramatically during the later half of the 20th century, reaching about 75 million by 2011. In recent years, however, Iran's birth rate has dropped significantly. Studies project that Iran's rate of population growth will continue to slow until it stabilizes above 100 million by 2050. More than half of Iran's population is under 35 years old (2012).
There is a vastly extended network of rivers in Iran most of which seasonally are filled with water. Some permanent rivers run from the Alborz or the Zagros to the Caspian Sea, Persian Gulf and Oman Sea.