Istanbul has been a cosmopolitan city throughout much of its history, but it has become more homogenized since the end of the Ottoman Empire. The vast majority of people across Turkey, and in Istanbul, are Muslim, and more specifically members of the Sunni branch of Islam. Most Sunni Turks follow the Hanafi school of Islamic thought, while Sunni Kurds tend to follow the Shafi'i school. The largest non-Sunni Muslim group, accounting 10-20% of Turkey's population, are the Alevis; a third of all Alevis in the country live in Istanbul. Mystic movements, like Sufism, were officially banned after the establishment of the Turkish Republic, but they still boast numerous followers. Istanbul is a migrant city. Since the 1950s, Istanbul's population has increased from 1 million to about 10 million residents. Almost 200,000 new immigrants, many of them from Turkey's own villages, continue to arrive each year. As a result, the city constant change, constantly reshaped to achieve the needs of these new population.
