Is there anything special that makes Germany have such stability for its head of government? [duplicate]

The following image shows the quite extraordinary political German stability in the government, namely how much a head of government can survive:

Wikipedia shows a somewhat similar situation in the last decades either: only three heads of government in almost four decades.

I am wondering about can the German political system can ensure such stability. The Netherlands comes near this stability, but the vast majority of other EU countries have a way bigger "fragmentation".