user: Question: Tell me the date for acts of 6 bands and year larger than 1981 for Monsters of Rock
Columns: ['Year', 'Date', 'Event', 'Days', 'Stages', 'Acts']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1980.0, '16 August', 'Monsters of Rock', '1 day', '1 stage', '8 bands']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Acts" = '6 bands' AND "Year" > 1981.0 AND "Event" = 'Monsters of Rock';