The lower, the better. The percentile of my grade in each course is calculated and then weighted by ECTS and the number of students in that course. This average shows the average percent of students that had better grades than me in my courses.

The lower, the better (a negative number is good). The Z-Score is a standardized score that allows to compare data points from different distributions. The standard score is calculated by subtracting the mean and dividing by the standard deviation. The units are standard deviations. The average shown here is made from the Z-scores calculated separately for each course and is weighted by ECTS and number of students in that course. We can see that in average my grades are about one standard deviation better than the mean grade in that course.

Total sum of ECTS credits so far. 180 are required for the degree. In Germany, each ECTS point is supposed to represent 30 hours of work.