Q&A: How Spain's mass regularisation of undocumented migrants will workThe mass regularisation of undocumented migrants is nothing new in Spain. Some of the more blatant anti-migrant rhetoric has also implied that regularising undocumented migrants means young, single African men arriving on boats are set to benefit the most, but the data disproves this. Funcas data shows 70 percent of undocumented migrants in Spain come from South American countries, while Central America and the Caribbean account for around 17 percent. Again, the data shows that the majority of undocumented migrants in Spain are of working age. According to CES conclusions, this younger demographic profile is because the vast majority of migrants arriving in Spain come for employment.