Since 1965, the US has seen increasingly large numbers of immigrants crossing its borders. Indeed, more immigrants are arriving now than at any point in the past; the 1990's saw a higher number of immigrants enter the US than any previous decade (INS 1999). A disturbing corollary to the recent explosion in immigration is the corresponding decline of immigrant earnings relative to the earnings of natives. A cursory glance at the literature strongly suggests the changing national origin of immigrants as the main cause of this relative earnings decline. As a prime example, Mexican immigrants now outnumber any other national group while having one of the biggest relative earnings gaps, with Mexican immigrant males earning on average some 50% less than males who were born in the US (Ruggles and Sobek, 1997).
Sanford '02, Jeremy, "English Language Proficiency and the Earnings of Mexican Immigrants" (2002). Honors Projects. Paper 32.