CREATE TABLE table_10664 ("Year" FLOAT, "Main colour ( s ) " TEXT, "Additional colour ( s ) " TEXT, "Livery" TEXT, "Additional major sponsor ( s ) " TEXT)

What is the average year of entries with additional color black?
SELECT AVG("Year") FROM table_10664 WHERE "Additional colour(s)" = 'black'
SELECT AVG("Year") FROM "table_10664" WHERE "Additional colour(s)" = 'black'