The "dollar a day" poverty line was first introduced in 1990 as a measure to meet such standards of living. For nations that do not use the U.S. dollar as currency, 'dollar a day' does not translate to living a day on the equivalent amount of local currency as determined by the exchange rate. Rather, it is determined by the purchasing power parity rate, which would look at how much local currency is needed to buy the same things that a dollar could buy in the United States. Usually, this would translate to having less local currency than if the exchange rate was used as the United States is a relatively more expensive country. From 1993 through 2005, the World Bank defined absolute poverty as $1.08 a day on such a purchasing power parity basis, after adjusting for inflation to the 1993 U.S. dollar and in 2008, it was updated as $1.25 a day (equivalent to $1.00 a day in 1996 US prices) and in 2015, it was updated as living on less than US$1.90 per day, and "moderate poverty" as less than $2 or $5 a day. Similarly, 'ultra-poverty' is defined by a 2007 report issued by International Food Policy Research Institute as living on less than 54 cents per day. The poverty line threshold of $1.90 per day, as set by the World Bank, is controversial. Each nation has its own threshold for absolute poverty line; in the United States, for example, the absolute poverty line was US$15.15 per day in 2010 (US$22,000 per year for a family of four), while in India it was US$1.0 per day and in China the absolute poverty line was US$0.55 per day, each on PPP basis in 2010. These different poverty lines make data comparison between each nation's official reports qualitatively difficult. Some scholars argue that the World Bank method sets the bar too high, others argue it is too low.