The Kingdom of Saudi Arabia is a country situated in Southwest Asia, the largest country of Arabia, by the Arabian Peninsula, bordering the Persian Gulf and the Red Sea, north of Yemen. Its extensive coastlines on the Persian Gulf and Red Sea provide great leverage on shipping (especially crude oil) through the Persian Gulf and the Suez Canal. The kingdom occupies 80% of the Arabian Peninsula. Most of the country's boundaries with the United Arab Emirates (UAE), Oman, and the Republic of Yemen (formerly two countries: the Yemen Arab Republic or North Yemen; and the People's Democratic Republic of Yemen or South Yemen) are undefined, so the exact size of the country remains unknown. The Saudi government estimate is at 2,217,949 square kilometres, while other reputable estimates vary between 2,149,690 and 2,240,000 sq. kilometres. Less than 7% of the total area is suitable for cultivation, and in the early 1960s, population distribution varied greatly among the towns of the eastern and western coastal areas, the densely populated interior oases, and the vast, almost empty deserts. External boundaries Saudi Arabia is bounded by seven countries and three bodies of water. To the west, the Gulf of Aqaba and the Red Sea form a coastal border of almost that extends to the southern part of Yemen and follows a mountain ridge for approximately to the vicinity of Najran. This section of the border with Yemen was demarcated in 1934 and is one of the few clearly defined borders with a neighbouring country. The Saudi border running southeast from Najran, however, is still undetermined. The undemarcated border became an issue in the early 1990s, when oil was discovered in the area and Saudi Arabia objected to the commercial exploration by foreign companies on behalf of Yemen. In the summer of 1992, representatives of Saudi Arabia and Yemen met in Geneva to discuss settlement of the border issue. To the north, Saudi Arabia is bounded by Jordan, Iraq, and Kuwait. The northern boundary extends almost from the Gulf of Aqaba on the west to Ras al Khafji on the Persian Gulf. In 1965, Saudi Arabia and Jordan agreed to boundary demarcations involving an exchange of areas of territory. Jordan gained of land on the Gulf of Aqaba and 6,000 square kilometers of territory in the interior, and 7,000 square kilometers of Jordanian-administered, landlocked territory was ceded to Saudi Arabia. In 1922, Ibn Saud and