The Educational Testing Service manages the SAT exam, and they released a report not too long ago that predicts a less skilled U.S. workforce in 2030 relative to today, with literacy rates declining by an average of 5% as unskilled immigration and rising rates of single parenthood take their toll. (If this is a duplicate, then apologies).

Some excerpts of their findings:

In particular, the survey revealed very strong links between the literacy proficiencies of workers and their access to knowledge-expert, managerial, and high-skill information-processing jobs.
Not surprisingly, the formal educational attainment of immigrants and their English-speaking skills were very strong predictors of their scores on national literacy assessments, including the IALS surveys. Overall, with their more limited years of schooling and weak English-speaking proficiencies, the immigrant population in the United States scored well below their native-born counterparts on recent literacy and numeracy assessments.
If America wants to compete on the same terms as it did in the past — making the most of the workers with low skill levels — then it must accept prevailing world wage levels for low-skilled and semi-skilled labor. That is we must be prepared for a massive decline in our standard of living. The alternative is to revise our view of the role of the worker in the economy. In the future, high-wage level societies will be those whose economies are based on the use of a wide scale of very skilled workers, backed up by the most advanced technologies available.
If we continue on our current course, however, it is likely that our nation will gradually lose ground in relation to other countries, becoming more divided both socially and economically in the process.
Unfortunately, current skill gaps coupled with demographic trends portend diminishing human capital among the future prime-working-age population of the United States.
http://www.ets.org/Media/Education_Topi ... tStorm.pdf