user: Question: What year was the Line of Gardermobanen completed?
Columns: ['Name', 'Location', 'Length in km (mi)', 'Year Completed', 'Line']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Seikan Tunnel', 'Japan ( Tsugaru Strait )', '53.9 (33.5)', '1988', 'Kaikyo Line ( Hokkaidō Shinkansen )']
SQL:

assistant: SELECT "Year Completed" FROM "Table" WHERE "Line" = 'Gardermobanen';