Encyclopedias have general information. They briefly describe the main ideas for different topics.
The first three books are in the library; the others are online (off campus you will be prompted to log in with your MyNOVA username and password):
The Newest Americans
Ref JV6455 .P57 2003
American Immigrant Cultures: Builders of a Nation
Ref E184 .A1 A63448 1997
Encyclopedia of North American Immigration
Ref JV6465 .P68 2005
This book has statistics near the end.