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

### Instruction:
What is the sum of Year(s), when Postion is 6th, and when Competition is Commonwealth Games?

### Inputs:
table_name: table, columns: ['Year', 'Competition', 'Venue', 'Position', 'Event']

### Response:
SELECT SUM Year FROM table WHERE Position = 6th AND Competition = commonwealth games