I researched the most common family names of countries in Europe and Asia. Now I will report the results.
The most common family name in England is Smith. In Germany it is Mu:ller which is often spelt Mueller in English. In the Netherlands the most common family name is De Jong. The most common Norwegian family name is Hansen. In Denmark the most common is Jensen and in Sweden it is Johansson.
The most common Finnish family name is Virtanen and the most common Hungarian one is Nagy. The most common Russian family name is Smirnov (sometimes spelt Smirnoff), the most common Polish one is Nowak, the most common Czech one is Novak and the most common Croatian one is Horvat.
The most common French family name is also a given name, Martin. The most common Spanish family name is Garci'a, the most common Portuguese one is Silva and the most common Italian one is Rossi.
Now I will focus on Asian family names. The most common Chinese family name is Wang (sometimes spelt Wong). The most common family name in Japan is Sato and in Korea it is Kim. The most common Vietnamese family name is Nguyen.
A list of the most common family names in different countries reveals that even in neighbouring countries with related languages the names are often quite different. In Denmark, Norway and Sweden the most common family names are Jensen, Hansen and Johansson respectively. However, in the Czech Republic and Poland they are virtually identical- Novak and Nowak. In the case of France, the most popular family name, Martin, is also a popular given name for men.