SKOLM02A is an inventory of students activitiesat the Danish music schools. A student may have several courses associated with different programs at a music school. The category 'unknown' is an invenory of students courses that have either had invalid personal data or have been removed because of discretion. The students who have a course, but unknown gender and age have invalid personal data. The students who have unknown courses are mainly removed because of discretion. The table SKOLM02B is an inventory of the unique number of students at the Danish music schools.