user: Question: What year was the most recent US Open championship?
Columns: ['Outcome', 'Year', 'Championship', 'Surface', 'Partner', 'Opponents in the final', 'Score in the final']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 2000.0, 'Wimbledon', 'Grass', 'Julie Halard', 'Serena Williams Venus Williams', '6–3, 6–2']
SQL:

assistant: SELECT MAX("Year") FROM "Table" WHERE "Championship" = 'US Open';