Original sentence: Approximately 55% of undergraduates that graduate complete their studies on time, and approximately 80% of them graduate within an additional year.Similar figures apply to graduate students.The Politecnico is widely known for being a selective and very difficult university, and as such, many students take one or more additional years to complete their studies.The figures are similar for the bachelor and the masters level graduates.The last survey of graduates  shows that 80% of graduates of the Politecnico di Milano finds a job within three months from graduation, and more than 90% within six months
Edited sentence: As confirmed by recent surveys (Piepoli, 2006), 70% of graduates of the Politecnico di Milano finds a job or an internship within three months from graduation, and 90% within six months.The Politecnico is widely known for being a selective and very difficult university, and as such, many students often drop out before graduation, take some additional years to complete their studies, and graduate with low marks