user: Question: What is the maximum ITV1 weekly ranking?
Columns: ['#', 'Airdate', 'No. of couples', 'First couple', 'Second couple', 'Third couple', 'Fourth couple', 'Viewers (millions)', 'ITV1 weekly ranking']
Types: ['real', 'text', 'real', 'text', 'text', 'text', 'text', 'text', 'real']
Sample row: [1.0, '2 January 2010', 3.0, 'Jim and Caroline', 'N/A', 'Rob and Jo-Jo', 'Adam and Charlene', '3.87', 22.0]
SQL:

assistant: SELECT MAX("ITV1 weekly ranking") FROM "Table";