As it was one of the official languages of the Austro-Hungarian Empire, German remained an important second language in much of Central and Eastern Europe long after World War I. Today, it is still the most common second language in some of the countries in the region (e.g. in Slovenia (45% of the pop.), Croatia (34%), the Czech Republic (31%) and Slovakia (28%)). In others, it is also known by significant numbers of the population (in Poland by 18%, in Hungary by 16%).