How many ranks by average for the couple Tana and Stuart?
CREATE TABLE table_28645 (
    "Rank by average" real,
    "Place" real,
    "Couple" text,
    "Total points" text,
    "Number of dances" real,
    "Average" text
)
SELECT COUNT("Rank by average") FROM table_28645 WHERE "Couple" = 'Tana and Stuart'
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 ranks by average for the couple Tana and Stuart? ### Input: CREATE TABLE table_28645 (
    "Rank by average" real,
    "Place" real,
    "Couple" text,
    "Total points" text,
    "Number of dances" real,
    "Average" text
) ### Response: SELECT COUNT("Rank by average") FROM table_28645 WHERE "Couple" = 'Tana and Stuart'