Bulgarian, and Chinese. There are more than 200,000 migrants from Sub-Saharan Africa living in Spain, principally Senegaleses and Nigerians. Since 2000, Spain has experienced high population growth as a result of immigration flows, despite a birth rate that is only half the replacement level. This sudden and ongoing inflow of immigrants, particularly those arriving illegally by sea, has caused noticeable social tension. Within the EU, Spain had the 2nd highest immigration rate in percentage terms after Cyprus, but by a great margin, the highest in absolute numbers, up to 2008. The number of immigrants in Spain had grown up from 500,000 people in 1996 to 5.2 million in 2008 out of a total population of 46 million. In 2005 alone, a regularisation programme increased the legal immigrant population by 700,000 people. There are a number of reasons for the high level of immigration, including Spain's cultural ties with Latin America, its geographical position, the porosity of its borders, 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. Another statistically significant factor is the large number of residents of EU origin typically retiring to Spain's Mediterranean coast. In fact, 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. In 2008, prior to the onset of the economic crisis, the Financial Times reported that Spain was the most favoured destination for Western Europeans considering a move from their own country and seeking jobs elsewhere in the EU. In 2008, the government instituted a "Plan of Voluntary Return" which encouraged unemployed immigrants from outside the EU to return to their home countries and receive several incentives, including the right to keep their unemployment benefits and transfer whatever they contributed to the Spanish Social Security. The programme had little effect; during its first two months, just 1,400 immigrants took up the offer. What the programme failed to do, the sharp and prolonged economic crisis has done from 2010 to 2011 in that tens of thousands of immigrants have left the country due to lack of jobs. In 2011 alone, more than half a million people left Spain. For the first time in decades the net migration rate was expected to be negative, and nine out of 10 emigrants were