* Definition of "student": The definition of "student" is broad. It includes K-12 students, undergraduate and graduate students, and students in vocational schools.
* Data Collection: Data on student residency is collected by various entities (school districts, universities, etc.) and isn't centrally compiled into a single, publicly accessible database covering all types of students.
* Fluctuation: The number of students in Illinois changes constantly due to enrollment shifts, graduations, and population changes.
To get an estimate, you'd need to combine data from multiple sources, which would be a significant research project.