user: Question: What is the average rank of the record on 2007-06-21 with a mark less than 91.29?
Columns: ['Rank', 'Mark', 'Athlete', 'Place', 'Date']
Types: ['real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 98.48, 'Jan Železný ( CZE )', 'Jena', '1996-05-25']
SQL:

assistant: SELECT AVG("Rank") FROM "Table" WHERE "Date" = '2007-06-21' AND "Mark" < 91.29;