Nauru is a phosphate rock island with rich deposits near the surface, which allowed easy strip mining operations. It has some remaining phosphate resources which, as of 2011, are not economically viable for extraction.[7] Nauru boasted the highest per-capita income enjoyed by any sovereign state in the world during the late 1960s and early 1970s. When the phosphate reserves were exhausted, and the island's environment had been seriously harmed by mining, the trust that had been established to manage the island's wealth diminished in value. To earn income, Nauru briefly became a tax haven and illegal money laundering centre. From 2001 to 2008, and again from 2012, it accepted aid from the Australian Government in exchange for hosting the Nauru detention centre. As a result of heavy dependence on Australia, many sources have identified Nauru as a client state of Australia.[8][9][10][11]