user: Question: What is the 1998 value if the 2011 value is 30.4?
Columns: ['1998', '2000', '2004', '2007', '2011']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1.5', '3.0', '11.0', '18.0', '30.4']
SQL:

assistant: SELECT "1998" FROM "Table" WHERE "2011" = '30.4';