user: Question: When was the most recent statue that was made out of solid granite completed?
Columns: ['Statue', 'Location', 'Height m', 'Height ft', 'Completed', 'Material']
Types: ['text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Statue of Liberty (Liberty Enlightening the World)', 'Liberty Island , New York', '46 m', '151ft', 1886.0, 'cast copper on metal armature']
SQL:

assistant: SELECT MAX("Completed") FROM "Table" WHERE "Material" = 'solid granite';