Calculate the percentage of high-level undergraduate course.
high-level undergraduate course refers to courseLevel = 'Level_400'; percentage = divide(count(course.course_id) when courseLevel = 'Level_400', count(course.course_id)) * 100%
SELECT CAST(SUM(CASE  WHEN courseLevel = 'Level_400' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) AS per FROM course
database name:db_id computer_student
course table course Cols: course id dtype integer, course level dtype text, 
person table person Cols: person ID dtype integer, professor dtype integer, student dtype integer, has position dtype text, in phase dtype text, years in program dtype text, 
advisedBy table advisedBy Cols: person id dtype integer, person id dummy dtype integer, 
taughtBy table taughtBy Cols: course ID dtype integer, person ID dtype integer, 
