user: Question: For how many years did Detroit have a passenger fare of $307.29?
Columns: ['Year', 'Lansing (LAN)', 'Detroit (DTW)', 'Grand Rapids (GRR)', 'Flint (FNT)', 'Kalamazoo (AZO)', 'Saginaw (MBS)']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [2006.0, '$370.61', '$322.83', '$413.74', '$298.89', '$472.93', '$441.26']
SQL:

assistant: SELECT COUNT("Year") FROM "Table" WHERE "Detroit (DTW)" = '$307.29';