<P> Commercial production of gas from the Songo Songo Island field in the Indian Ocean commenced in 2004, thirty years after it was discovered there . Over 35 billion cubic feet of gas was produced from this field in 2013, with proven, probable, and possible reserves totalling 1.1 trillion cubic feet . The gas is transported by pipeline to Dar es Salaam . As of 27 August 2014, TANESCO owed the operator of this field, Orca Exploration Group Inc . </P> <P> A newer natural gas field in Mnazi Bay in 2013 produced about one - seventh of the amount produced near Songo Songo Island but has proven, probable, and possible reserves of 2.2 trillion cubic feet . Virtually all of that gas is being used for electricity generation in Mtwara . </P> <P> The Ruvuma and Nyuna regions of Tanzania have been explored mostly by the discovery company that holds a 75 percent interest, Aminex, and has shown to hold in excess of 3.5 trillion cubic feet of natural gas . A pipeline connecting offshore natural gas fields to Tanzania's commercial capital Dar es Salaam was completed at the end of April 2015 . </P> <P> Travel and tourism contributed 17.5 percent of Tanzania's gross domestic product in 2016 and employed 11.0 percent of the country's labour force (1,189,300 jobs) in 2013 . Overall receipts rose from US $1.74 billion in 2004 to US $4.48 billion in 2013, and receipts from international tourists rose from US $1.255 billion in 2010 to US $2 billion in 2016 . In 2016, 1,284,279 tourists arrived at Tanzania's borders compared to 590,000 in 2005 . The vast majority of tourists visit Zanzibar or a "northern circuit" of Serengeti National Park, the Ngorongoro Conservation Area, Tarangire National Park, Lake Manyara National Park, and Mount Kilimanjaro . In 2013, the most visited national park was Serengeti (452,485 tourists), followed by Manyara (187,773) and Tarangire (165,949). </P>

Tanzania is the size of what us state