Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Ship | Built | In service for NAL | Type | Tonnage |
| --- | --- | --- | --- | --- |
| SSKristianiafjord | 1913.0 | 1913–17 | ocean liner | GRT |
| SSBergensfjord | 1913.0 | 1913–40 | ocean liner | GRT |
| SSStavangerfjord | 1917.0 | 1917–40 1945–64 | ocean liner | GRT |
| MSOslofjord(1938) | 1938.0 | 1938–40 | ocean liner | GRT |
| MSOslofjord(1949) | 1949.0 | 1949–67 | ocean liner | GRT |
| MSBergensfjord | 1956.0 | 1956–71 | ocean liner | GRT |
| MSSagafjord | 1965.0 | 1965–83 | ocean liner / cruise ship | GRT |
| MS Vistafjord | 1973.0 | 1973–83 | cruise ship | GRT |
Question:
The ship SSBergensfjord built before 1973 has what tonnage?
Answer:
GRT