a member of the United Nations, but a number of states, including the United States and various members of the European Union, have recognised Republic of Kosovo as a sovereign state. Languages Serbo-Croatian, the only language taught across former Yugoslavia, remained the second language of many Slovenes and Macedonians, especially those born during the time of Yugoslavia. After the breakup of Yugoslavia, Serbo-Croatian has lost its unitary codification and its official unitary status and has since diverged into four standardized varieties of what remains one pluricentric language: Bosnian, Croatian, Montenegrin and Serbian. Yugo-nostalgia Remembrance of the time of the joint state and its positive attributes is referred to as Yugo-nostalgia. Many aspects of Yugo-nostalgia refer to the socialist system and the sense of social security it provided. There are still people from the former Yugoslavia who self-identify as Yugoslavs; this identifier is commonly seen in demographics relating to ethnicity in today's independent states. Demographics Yugoslavia had always been a home to a very diverse population, not only in terms of national affiliation, but also religious affiliation. Of the many religions, Islam, Roman Catholicism, Judaism, and Protestantism, as well as various Eastern Orthodox faiths, composed the religions of Yugoslavia, comprising over 40 in all. The religious demographics of Yugoslavia changed dramatically since World War II. A census taken in 1921 and later in 1948 show that 99% of the population appeared to be deeply involved with their religion and practices. With postwar government programs of modernisation and urbanisation, the percentage of religious believers took a dramatic plunge. Connections between religious belief and nationality posed a serious threat to the post-war Communist government's policies on national unity and state structure. Although Yugoslavia became a nominally atheist state, in contrast to other socialist states of the time, Catholic Church maintained an active role in society of Yugoslavia, the Holy See normalized its relations with Yugoslavia by 1967 and worked together on stopping the Vietnam War. Likewise, the Serbian Orthodox Church received favorable treatment, and Yugoslavia did not engage in anti-religious campaigns to the extent of other countries in the Eastern Bloc. After the rise of communism, a survey taken in 1964 showed that just over 70% of the total population of Yugoslavia considered themselves to be religious believers. The places of highest religious concentration were that of Kosovo with 91% and Bosnia and Herzegovina with 83.8%. The places of lowest religious concentration were