Islam is the most common religion in Sudan, and Muslims have dominated national government institutions since independence in 1956. According to UNDP Sudan, the Muslim population is 97%, including numerous Arab and non-Arab groups. The remaining 3% ascribe to either Christianity or traditional animist religions. Muslims predominate in all but Nuba Mountains region. The vast majority of Muslims in Sudan adhere to Sunni Islam of Maliki school of jurisprudence, deeply influenced with Sufism. There are also some Shia communities in Khartoum, the capital. The most significant divisions occur along the lines of the Sufi brotherhoods. Two popular brotherhoods, the Ansar and the Khatmia, are associated with the opposition Umma and Democratic Unionist Parties respectively. Only the Darfur region is traditionally lacking the presence of Sufi brotherhoods found in the rest of the country.