user: Question: What is the average opened year of the line with 59 stations served and more than 145000000 journeys made per annum?
Columns: ['Line name', 'Opened', 'Last extension', 'Stations served', 'Length', 'Average Interstation', 'Journeys made (per annum)']
Types: ['text', 'real', 'real', 'real', 'text', 'text', 'real']
Sample row: ['Line A', 1977.0, 1994.0, 46.0, '108.5km / 67.5miles', '2,411m', 272800000.0]
SQL:

assistant: SELECT AVG("Opened") FROM "Table" WHERE "Stations served" = 59.0 AND "Journeys made (per annum)" > 145000000.0;