Kids have a holiday break from school this month, but when they return to class in January, there's a 1 in 10 chance that they'll return to a private, rather than public, school. According to the National Center for Education Statistics (NCES), 5.2 million students were enrolled in private school in the fall of 1999 (the latest year for which data is available), a slight increase over 5.1 million students in the fall of 1997. (Private school students still represent only 10 percent of elementary and secondary school students in the United States.) More than 4 in 5 of these private school kids (84 percent) were enrolled in parochial schools. With 49 percent of all private school students educated within the Catholic school system, Catholic schools claimed the largest share of the crop.