Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
How many ranks by average for the couple Tana and Stuart?

### Inputs:
table_name: table, columns: ['Rank by average', 'Place', 'Couple', 'Total points', 'Number of dances', 'Average']

### Response:
SELECT COUNT Rank by average FROM table WHERE Couple = Tana and Stuart