How many 'ghost migrants' are living in Europe?

Refugees fleeing from intractable wars in Syria, Iraq and Afghanistan have received the lions share of media attention this year. Yet, while the number is in the hundreds of thousands, experts estimate that they are a minority of those arriving illegally on the continent annually. They're far outnumbered by economic migrants, those not fleeing from violence. In this America Tonight excerpt, Sheila MacVicar meets two former workers from Ghana and Sudan who are now fighting for the largely-ignored migrant workers in Italy.