How many years had the best actress in a Revival category?
CREATE TABLE table_47434 (
    "Year" real,
    "Award" text,
    "Category" text,
    "Nominated work" text,
    "Result" text
)
SELECT COUNT("Year") FROM table_47434 WHERE "Category" = 'best actress in a revival'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: How many years had the best actress in a Revival category? ### Input: CREATE TABLE table_47434 (
    "Year" real,
    "Award" text,
    "Category" text,
    "Nominated work" text,
    "Result" text
) ### Response: SELECT COUNT("Year") FROM table_47434 WHERE "Category" = 'best actress in a revival'