Although it had been occupied for thousands of years by indigenous peoples, from the 18th century onward, European powers considered the territory of Alaska ripe for exploitation. The United States purchased Alaska from Russia on March 30, 1867, for $7.2 million ($121 million adjusted for inflation) at approximately two cents per acre ($4.74/km²). The area went through several administrative changes before becoming organized as a territory on May 11, 1912. It was admitted as the 49th state of the U.S. on January 3, 1959. The name “Alaska” (Аляска) had been introduced in the Russian Colonial Period, when it was used to refer to the peninsula. It was derived from an Aleut Idiom, which figuratively refers to the mainland of Alaska. Alaska is the larges state in the USA by area and the least densely populated of the 50 United States. Alaska’s economy is dominated by the oil, natural gas and fishing industries, resources which it has in abundance. Tourism is also a significant part of the economy.