There are a total of 50 races that count, with the best result being 1018 and the worst being 2490. The resulting handicap score is 1129.
The blue line shows the results over time (the lower the better, most recent results on the right), while the purple line shows the individual scores sorted by magnitude (lowest on the left, worst on the right). The mid-point of that line is the median, and will be the actual handicap score. This is indicated by the green line. A result below the green line means that it was better than the handicap, one above the line was worse.