The modern petroleum industry is generally considered to have started in 1859, when the first well ever drilled for the specific purpose of locating oil was successful at Titusville, Pennsylvania, close to natural seepages, at a depth of only 69 feet. This development quickly spread in the USA and to other countries, notably the Caucasus in Tsarist Russia, where the great oilfields of Baku were found in the 1870s. By the end of the following decade, these surpassed for a short period the output of the USA. (Since 1974 crude oil production in the USSR has again exceeded that from the USA-BP Statistical Review of the World Oil Industry 1979).