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

### Instruction:
Competition of u.s championships, and a Event of all around has what average year?

### Inputs:
table_name: table, columns: ['Year', 'Competition', 'Location', 'Event', 'Final-Rank', 'Final-Score']

### Response:
SELECT AVG Year FROM table WHERE Competition = u.s championships AND Event = all around