Before the discovery of oil, the economy of the Qatari region focused on fishing and pearl hunting. A report prepared by local governors of Ottoman Empire in 1892 states that total income from pearl hunting in 1892 is 2,450,000 kran. After the introduction of the Japanese cultured pearl onto the world market in the 1920s and 1930s, Qatar's pearling industry crashed. Oil was discovered in Qatar in 1940, in Dukhan Field. The discovery transformed the state's economy. Now, the country has a high standard of living for its legal citizens. With no income tax, Qatar (along with Bahrain) is one of the countries with the lowest tax rates in the world. The unemployment rate in June 2013 was 0.1%. Corporate law mandates that Qatari nationals must hold 51% of any venture in the emirate. Trade and industry in the emirate is overseen by the Ministry of Business and Trade.