user: Question: What is the average year of entries with additional color Black?
Columns: ['Year', 'Main colour(s)', 'Additional colour(s)', 'Livery', 'Additional major sponsor(s)']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1978.0, 'Yellow', 'Black', 'ATS Wheels', 'Ford, Champion, Air Press, Shell, Goodyear']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Additional colour(s)" = 'Black';