The high plains are located at the foot of the Andes and are very rich land for cultivation. The Apure River crosses the western plains from west to east, its torrent being fed in the north by the inflows of the Uribante, Sarare, Caparo, Suripa, Ticoporo, Canaguá, Mamparo, Santo Domingo, Portuguesa and Guárico Rivers. To the south and east are the Meta, Cinaruco, Capanaparo, Arauca and Arichuna rivers, while going east, the Guariquito, Manapire, Zuata, Pao and Caris rivers also join the course of the great Orinoco river, from its northern slope. The economy of the Llanera region is dominated by agricultural and livestock activities and to a lesser extent by activities such as tourism. However, it remains a purely rural and sparsely populated region. This is an area of special importance for the country's agriculture and livestock, especially with regard to cattle, pigs and goats. Agricultural activity was even more decisive before 1917, when oil exploitation began to take off. However, later on and because of the rural exodus, the primary sector lost importance at a national level, but it maintains a relative boom in the region. It is located in the center of the country, in the region of Los Llanos, bordering Carabobo, Aragua and Miranda to the north, Anzoátegui State to the east, Bolivar and Apure to the south, and Barinas and Cojedes to the west. With almost 65 000 km² it is the fourth largest state - behind Bolivar, Amazonas and Apure - with 746 174 inhabitants in 2011, the ninth least populated. Apure, this is the largest plain state in the region. Its plains are properly divided into three major parts: the low, middle, and high plains, as well as the low Apure, middle Apure, and high Apure. Its main economic activities are cattle raising followed by agriculture and fishing, the state is poor in production with only 11% of its entire territory in production. The most important cities are: San Fernando de Apure, Achagua, Elorza and Guasdualito. The state is crossed by numerous rivers of great length and width, all of which are part of the Orinoco basin. The Apure, the most important of these, is also the main Venezuelan tributary of the Orinoco from its left bank, and the second longest in the country: it runs for about 1000 km between its source and its mouth.