Tourism contributed 2.8 percent to the Omani GDP in 2016. It grew from RO 505 million (US$1.3 billion) in 2009 to RO 719 million (US$1.8 billion) in 2017 (+42.3 percent growth). Citizens of the Gulf Cooperation Council (GCC), including Omanis who are residing outside of Oman, represent the highest ratio of all tourists visiting Oman, estimated to be 48 percent. The second highest number of visitors come from other Asian countries, who account for 17 percent of the total number of visitors. A challenge to tourism development in Oman is the reliance on the government-owned firm, Omran, as a key actor to develop the tourism sector, which potentially creates a market barrier-to-entry of private-sector actors and a crowding out effect. Another key issue to the tourism sector is deepening the understanding of the ecosystem and biodiversity in Oman to guarantee their protection and preservation.