The Census Bureau does not have any specific citation style recommendations and encourages the researcher to choose a style
Basic Format for APA 6th edition
U.S. Census Bureau (year data was published). Name of data or report. Retrieved from [URL].
Chicago Style 16th ed.
United States Census Bureau. Name of Table. Data.Census.Gov <URL> (The date the Table was generated)
See the Publication Manual of the American Psychological Association. This book is available at multiple locations in the library system.