Home schooling is the process of educating school-aged children at home rather than at a school. As of the early 2000s, it is perhaps one of the fastest growing trends in education in the United States. Since 1993, the practice has been legal in all 50 states. About 1.1 million students were being home-schooled in the spring of 2003, according to the National Household Education Surveys Program (NHES), which was conducted by the United States Department of Education. In addition, the percentage of the school-age population that was being home-schooled increased from 1.7 percent in 1999 to 2.2 percent in 2003. Parents choose to home-school their children for a variety of reasons, though certain factors appear to be more prevalent than others. Nearly two-thirds of the parents of home-schooled students reported that their primary reason for home schooling was either concern regarding the environment of schools or a wish to provide moral or religious instruction.