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

### Instruction:
What is the average grid for vehicles manufactured by Aprilia and having run more than 16 laps?

### Inputs:
table_name: table, columns: ['Rider', 'Manufacturer', 'Laps', 'Time', 'Grid']

### Response:
SELECT AVG Grid FROM table WHERE Manufacturer = aprilia AND Laps > 16