Oil was known to exist in western Turkmenistan as early as the 18th century. General Aleksey Kuropatkin reported in 1879 that the Cheleken Peninsula had as many as three thousand oil sources. Turkmen settlers in the 19th century extracted oil near the surface and shipped it to Astrakhan by ship and to Iran by camel caravan. Commercial oil drilling began in the 1890s. The oil extraction industry grew with the exploitation of the fields in Cheleken in 1909 (by Branobel) and in Balkanabat in the 1930s. Production leaped ahead with the discovery of the Gumdag field in 1948 and the Goturdepe field in 1959. By 1940 production had reached two million tons per year, by 1960 over four million tons, and by 1970 over 14 million tons. Oil production in 2019 was 9.8 million tons.