In 2007 they introduced a unique tax number for every natural person.

In fact, assigning these numbers was complicated by the fact that there is no central registration data base. They started from all the local data bases and then filtered this data to remove duplicates.

Source: https://de.wikipedia.org/wiki/Steuerliche_Identifikationsnum... (sorry, German only)

German people comply to taxation laws, as no one else in Europe does ;)