The economy of Peru is the 48th largest in the world (ranked by Purchasing Power Parity), and the income level is classified as "upper middle" by the World Bank. Peru is, , one of the world's fastest-growing economies owing to an economic boom experienced during the 2000s. It has an above-average Human Development Index of 0.74 which has seen steady improvement over Historically, the country's economic performance has been tied to exports, which provide hard currency to finance imports and external debt payments. Although they have provided substantial revenue, self-sustained growth and a more egalitarian distribution of income have proven elusive. According to 2015 data, 19.3% of its total population is poor, including 9% that lives in extreme poverty. Inflation in 2012 was the lowest in Latin America at only 1.8%, but increased in 2013 as oil and commodity prices rose; it stands at 2.5%. The unemployment rate has fallen steadily and stands at 3.6%.