Illegal Immigration in Espana

The other day I was walking home from the beach. I was passing a bunch of vendors selling purses, jerseys, sunglasses, and other things. I was walking with my head phones in so I could not hear any sounds around me. All of a sudden the vendors grabbed up their sheets with all of their goods and started running. I looked up and saw two police men walking down the esplanada. This experience brought the question of illegal immigration quickly to my mind. What is immigration like in spain? Is it as big of a problem in spain as it is in the states? Is it hard for immigrants to enter the country? Where are most of the illegal immigrants from?

I looked up some research on it and found that in the last decade the amount of illegal immigration has decreased. I found some interesting numbers here.