How many deciles have an Authority of state and a Name of chertsey school?
CREATE TABLE table_14989 (
    "Name" text,
    "Years" text,
    "Gender" text,
    "Area" text,
    "Authority" text,
    "Decile" real,
    "Roll" real
)
SELECT COUNT("Decile") FROM table_14989 WHERE "Authority" = 'state' AND "Name" = 'chertsey school'
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 deciles have an Authority of state and a Name of chertsey school? ### Input: CREATE TABLE table_14989 (
    "Name" text,
    "Years" text,
    "Gender" text,
    "Area" text,
    "Authority" text,
    "Decile" real,
    "Roll" real
) ### Response: SELECT COUNT("Decile") FROM table_14989 WHERE "Authority" = 'state' AND "Name" = 'chertsey school'