As it is known, before 1991 Azerbaijan was part of the Union of Soviet Socialist Republics Union (USSR). The economy had the character of planned economy and was inseparably linked with the economies of other Soviet Republics. Azerbaijan due to its rich natural resources was one of the largest and important economic centres of the Soviet Union and had very developed industry (oil and natural gas exploration, oil machinery, chemical and petrochemical production, metallurgy etc.), as well as agriculture (cotton, livestock, vegetables and fruits, cereal, tea, silk etc.).