In 2001, the Custom Service processed 472 million people, of which 500,000 were bona fide immigrants and 28 million tourists, foreign students and business travelers. Immigrants help the United States grow and prosper. It is estimated that there are over 564,000 foreign students in the United States; 4.41 million business travelers, and 23.25 million tourists. Among immigrants, 20% are medical doctors, 22.7% Ph.Ds, 10.7 % sell-employed, and 26% of U.S. patents created by foreign-born people. At Stevens Institute of Technology, New Jersey, 48 percent of doctorates awarded in 2001 went to foreign students. A third of the technical work force in Silicon Valley are foreign born scientists and engineers. Says Anna Lee Saxenian of the University of California at Berkeley, fully a quarter of the high-tech companies started in Silicon Valley are run by Chinese and Indians. (Source: "Don't slam the door," by Tamar Jacoby, Reader's Digest, March 2002).