In order to meet the requirement to enroll a substantial portion of the pupils in one or more grades for a substantial portion of a school day under s. 118.50(1)(intro.), Stats., a whole grade sharing agreement shall provide for at least 20 percent of the pupils enrolled in each affected grade of a district of residence to attend a district of attendance for at least 20 percent of a school day.
Wis. Admin. Code Department of Public Instruction PI 33.03