Navigation statistics comprises all movements of marine navigation from and to the four ports Doha, Messaieed, Halul, and Ras Laffan. It does not include coastal movements of ships and boats that perform activity within the regional boundaries of the state of Qatar. Data on vessel movements are displayed in monthly tables showing arrivals and departures. Data are compiled on the number of vessels categorized by tonnage (gross and net), by country of registration for arrivals /country of destination for departures, type of vessel, tonnage category, and previous port. Data is collected from the sources by coordinating with them electronically, through emails. Periodicity: the navigation data is published monthly in Qatar Monthly statistics ,and it is annually published in the Annual Bulletin on Navigation statistics.