user: Question: What was the minimum % funded of the project that was closed on 2012-05-18?
Columns: ['Rank', 'Total USD', 'Project name', 'Creator', 'Category', '% funded', 'Backers', 'Closing date']
Types: ['real', 'real', 'text', 'text', 'text', 'real', 'real', 'text']
Sample row: [1.0, 10266845.0, 'Pebble: E-Paper Watch for iPhone and Android', 'Pebble Technology', 'Design', 10266.0, 68928.0, '2012-05-18']
SQL:

assistant: SELECT MIN("% funded") FROM "Table" WHERE "Closing date" = '2012-05-18';