user: Question: What is the average year for Team Oreca?
Columns: ['Year', 'Team', 'Co-Drivers', 'Class', 'Laps', 'Pos.', 'Class Pos.']
Types: ['real', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: [1997.0, 'Viper Team Oreca', 'Tommy Archer Marc Duez', 'GT2', 76.0, 'DNF', 'DNF']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Team" = 'Team Oreca';