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

### Instruction:
what is the number of sites when the number of screens is 687 and rank is more than 7?

### Inputs:
table_name: table, columns: ['Rank', 'Circuit', 'Headquarters', 'Screens', 'Sites']

### Response:
SELECT AVG Sites FROM table WHERE Screens = 687 AND Rank > 7