The overriding impact of immigrants is to strengthen and enrich American culture, increase the total output of the economy, and raise the standard of living of American citizens. Immigrants are advantageous to the United States for several reasons: (1) Since they are willing to take a chance in a new land, they are self-selected on the basis on motivation, risk taking, work ethic, and other attributes beneficial to a nation. (2) They tend to come to the United States during their prime working years (the average age is 28), and they contribute to the workforce and make huge net contributions to old-age entitlement programs, primarily Social Security. (3) Immigrants tend to fill niches in the labor market where demand is highest relative to supply, complementing rather than directly competing with American workers. (4) Many immigrants arrive with extremely high skill levels, and virtually all, regardless of skill level, bring a strong desire to work. (5) Their children tend to reach high levels of achievement in American schools and in society at large.