Oil. Other mineral resources that exist in significant quantities in the region include coal, copper, gold, iron, limestone (which is used to produce cement), marble, and zinc. The world's largest deposit of rock sulfur is located just southwest of Erbil. In July 2012, Turkey and the Kurdistan Regional Government signed an agreement by which Turkey will supply the KRG with refined petroleum products in exchange for crude oil. Crude deliveries are expected to occur on a regular basis. Demographics Due to the lack of a proper census, the exact population and demographics of Kurdistan Region are unknown, but the government has started to publish more detailed figures. The population of the region is notoriously difficult to ascertain, as the Iraqi government has historically sought to minimize the importance of the Kurdish minority while Kurdish groups have had a tendency to exaggerate the numbers. Based on available data, Kurdistan has a young population with an estimated 36% of the population being under the age of 15. Ethnic data (1917–1947) Religion Kurdistan has a religiously diverse population. The dominant religion is Islam, which is professed by the majority of Kurdistan Region's inhabitants. These include Kurds, Iraqi Turkmen, and Arabs, belonging mostly to the Shafi'i school of Sunni Islam. There is also a small number of Shia Feyli Kurds. In 2015, the Kurdistan Regional Government enacted a law to formally protect religious minorities. Christianity is professed by Assyrians and Armenians. Yazidis make up a significant minority, with some 650,000 in 2005, or 560,000 as of 2013, The Yarsan (Ahl-e Haqq or Kakai) religion numbers around 200,000 adherents respectively. In 2020, it was reported that 60 Zoroastrian families live in Iraqi Kurdistan. The first Zoroastrian temple was opened in the city of Sulaymaniyah (Silêmanî) in September 2016. A tiny ethno-religious community of Mandaeans also exists within the semi-autonomous region. The National Association of Jews from Kurdistan in Israel stated there is a small number of expatriate Jews in the Kurdistan Region, but no Jews remaining from original Jewish communities. Immigration Widespread economic activity between the Kurdistan Region and Turkey has given the opportunity for Kurds in Turkey to seek jobs in the Kurdistan Region. A Kurdish newspaper based in the Kurdish capital estimates that around 50,000 Kurds from Turkey are now living in the Kurdistan Region. Refugees The Kurdistan Region is hosting 1.2 million displaced Iraqis who have been displaced by the ISIS war,