The latest available figures are for a passenger throughput at Dublin Airport of approximately 10 million to end September 1999. The estimated figure for the whole of 1999 is 13 million. The 1998 joint Aer Rianta-CIE air-rail link study reported that passenger throughput represented one-third of all surface trips to-from the airport. On this basis the total number of trips, including passengers, meeters and greeters and staff working at the airport, will be about 40 million this year. A number of options for a rail link are currently under consideration. In May 1998 the Government approved the extension of the light rail system to Dublin Airport. Public consultation on this line is ongoing and a number of options on how to serve the airport are under consideration. The strategic planning guidelines for the greater Dublin area recommended additional study of a heavy rail link to the airport and identified a number of options.