The meaning of 50% drop out rate

I. the other day provided very interesting insider feedback on a conference that was held in Paris about Japanese studies in France. The trend is not limited to France but something of a tsunami took place sometimes in the second half of the 80s when Japanese language teaching started to seep into high schools. When I started learning Japanese in Paris, there were nationally two faculties teaching the language. Now, and despite Chinese beating Japanese soon, training in Japanese is offered in many universities over the country. The new Japonism that started to grow at the same time has fueled the interest for the language. I. mentioned a concern of the teaching community there, being the fact that the drop-out rate is some 50%. If I remember well the drop out rate over some 4 years when I was learning in Paris was probably around 90%, which suggests that things has improved tremendously. I am concerned by the meaning of this concern.