Other significant European origins include Slovak, German, Irish, Norwegian, Polish, French, Portuguese, Swedish, Greek, Czech, Albanian, Croatian, Slovenian, Dutch, Russian, Serbian, English, Hungarian and Bulgarian. In the 1980s and 1990s, there was a small wave of immigration from Romania and Ukraine. There is a minority of ''criollo'' citizens, dating back to the Spanish colonial days. The ''Criollo'' and Spanish-aboriginal (mestizo) population in the city has increased mostly as a result of immigration from the inner provinces and from other countries such as neighboring Bolivia, Paraguay, Chile and Peru, since the second half of the 20th century. 