As of 2005 Spain had the second highest immigration rates within the EU, just after Cyprus, and the second highest absolute net migration in the World (after the USA). This can be explained by a number of reasons including its strong economic growth at the time, the large size of its underground economy and the strength of the agricultural and construction sectors which demand more low cost labour than can be offered by the national workforce, as well as business opportunities for immigrants coming from other developed countries. In fact, booming Spain was Europe's largest absorber of migrants from 2002 to 2007, with its immigrant population more than doubling as 2.5 million people arrived.