Why do you suppose that there are

 

   2 different curves for the U.S.  ?

 

                       next*

 

 

 

 
     Answer  =  IMMIGRATION...
                                                    The Immigration and Nationality Act of 1965
                                                     has changed the population profiles of the United States

    Since 196527 million legal immigrants have come to U.S.    &      10.3 million illegals
                        
as of today the U.S. population is about 305 million

    in 2004      -  U.S. has 34.2 million foreign-born residents [11.3% of U.S. population]
                          - 3.3% of them hold higher education degrees, compared to 2.2% of native borns
                          - they pay more in Federal taxes than they receive in govt. benefits (edu/ssn)

    by 2004         - 2/3 have settled in just 6 states [ FL, CA, TX, NY, IL, & NJ ]     

                                      see map*

 

 

    

 

 



   back                                                                                  source: Scientific American: Vol. 293, No. 2, page 25, 2005.