The government is facing a major re-think of its immigration policy, armed with new figures which show that almost half of the migrants living in Greece are doing so illegally, according to research conducted by Interior Ministry officials. Greece is home to between 900,000 and 1.2 million immigrants, some 400,000 of whom do not have legal papers. It is estimated that there are almost 200,000 applications for residency permits currently outstanding, 15 years after significant numbers of migrants first began arriving in Greece. Two relatively unsuccessful efforts to legalize immigrants have prompted the government to examine ways of updating policies to deal with the backlog and be more efficient in handling future immigration. Interior Ministry sources told Kathimerini that one method that might be considered is dividing immigrants into several subcategories, such as seasonal workers, in order to facilitate recording their details and processing them for legalization. Greece has the highest proportion of immigrants of any EU member state and the Interior Ministry has asked the Immigration Policy Institute (IPI) to oversee five different academic studies on the facts and figures surrounding migrants in Greece in order to arm it with the necessary data to form its revised policies. So far, research shows that although immigrants have traveled from 27 different countries to live and work in Greece, over half of them come from one country – Albania. Some 55 percent of immigrants in Greece are Albanian, with five other former Communist bloc countries (Bulgaria, Georgia, Romania, Russia and Ukraine) taking up spots in the top 10. Cyprus with 2.4 percent and the UK and Germany with 1.9 percent are the biggest sources of migrants into Greece among EU member states. The highest non-European country is the USA, whose nationals make up 2.8 percent of the immigrant population. Although, officially, illegal immigrants cannot register their children in Greek schools, some 150,000 children of immigrants attend classes.