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

### Instruction:
What is the average year that anna thompson had an 8th place result in team competition at the world cross country championships in st etienne, france with

### Inputs:
table_name: table, columns: ['Year', 'Tournament', 'Venue', 'Result', 'Extra']

### Response:
SELECT AVG Year FROM table WHERE Tournament = world cross country championships AND Venue = st etienne, france AND Extra = team competition AND Result = 8th