user: Question: What year was the Timber Trade?
Columns: ['Year', 'Theme', 'Artist', 'Mintage', 'Issue Price']
Types: ['real', 'text', 'text', 'real', 'text']
Sample row: [2005.0, 'Fur Traders', 'John Mardon', 4500.0, '$489.95']
SQL:

assistant: SELECT "Year" FROM "Table" WHERE "Theme" = 'Timber Trade';