user: Question: How many yards per attempt have net yards greater than 631?
Columns: ['Player', 'Attempts', 'Net yards', 'Yards per attempt', 'Touchdowns']
Types: ['text', 'real', 'real', 'real', 'real']
Sample row: ['Mel Anthony', 145.0, 702.0, 4.8, 9.0]
SQL:

assistant: SELECT COUNT("Yards per attempt") FROM "Table" WHERE "Net yards" > 631.0;