user: Question: What ship size had a cargo value of $31,750 in 2006?
Columns: ['Ship size', 'Cargo', '2004', '2005', '2006']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Ship size', 'Cargo', '2004', '2005', '2006']
SQL:

assistant: SELECT "Ship size" FROM "Table" WHERE "2006" = '$31,750';