In Russia, industrial production measures the output of businesses integrated in industrial sector of the economy. Manufacturing is the most important sector and accounts for 55 percent of total production. The biggest segments within manufacturing are: metallurgy (9.6 percent); coke and refined petroleum products (9.5 percent); food beverages and tobacco (8.4 percent); chemicals (4 percent); machinery and equipment (3.8 percent); transport (3.7 percent) and electrical equipment (3.4 percent). Mining and quarrying accounts for 35 percent, and natural gas and crude oil exploration represents 29 percent of total output. Also, electricity, gas and water supply accounts for 11 percent.