20 USC 4359a - International students

(a) Enrollment 
Effective with new admissions for academic year 19931994 and each succeeding academic year, the University (including preparatory, undergraduate, and graduate students) and NTID shall limit the enrollment of international students to approximately 15 percent of the total postsecondary student population enrolled respectively at the University or NTID, except that in any school year no United States citizen who is qualified to be admitted to the University or NTID and applies for admission to the University or NTID shall be denied admission because of the admission of an international student.
(b) Tuition surcharge 
Effective with new admissions, the tuition for postsecondary international students enrolled in the University (including preparatory, undergraduate, and graduate students) or NTID shall include a surcharge of 100 percent for the academic year 19992000 and any succeeding academic year.
(c) Reduction of surcharge 
Beginning with the academic year 19931994, the University or NTID may reduce the surcharge under subsection (b) of this section to 50 percent if
(1) a student described under subsection (b) of this section is from a developing country;
(2) such student is unable to pay the tuition surcharge under subsection (b) of this section; and
(3) such student has made a good faith effort to secure aid through such students government or other sources.
(d) “Developing country” defined 
For purposes of subsection (c) of this section, the term developing country means a country that has a 1990 per capita income not in excess of $4,000 in 1990 United States dollars.