Though the majority of the population is Muslim, other religions include Hinduism, Christianity and even Judaism because of a large incoming of immigrants and workers from non-Islamic countries; India, Philippines and Sri Lanka. Bahrainis are known for their tolerance and the country has transitioned into a cosmopolitan society with mixed communities. Two thirds of the population is made up of Arabs while the rest of the people are of Iranian descent as well as from South Asia and Southeast Asia. Expatriates make up 30% of the population.Arabic is the official language of the people of Bahrain though English is widely used. The discovery of petroleum means that the Bahrainis have the fastest growing economy in the Arab world. However, unemployment, particularly among the young, and the reduction of both oil and underground water resources are crucial long-term economic problems.