user: Question: Name the date of report for tier 1 ratio being 3.9%
Columns: ['Institution', 'Date of report', 's Risk-weighted asset , € million', 'Tier 1 Capital, € million', 'Tier 1 ratio']
Types: ['text', 'text', 'real', 'real', 'text']
Sample row: ['Allied Irish Banks', '30 June 2009', 131327.0, 10249.0, '7.8%']
SQL:

assistant: SELECT "Date of report" FROM "Table" WHERE "Tier 1 ratio" = '3.9%';