SELECT AVG(year) FROM table_name_22 WHERE tournament = "world cross country championships" AND venue = "st etienne, france" AND extra = "team competition" AND result = "8th"
Berapa tahun rata -rata Anna Thompson memiliki tempat ke -8 menghasilkan kompetisi tim di Kejuaraan Lintas Negara Dunia di St Etienne, Prancis dengan
CREATE TABLE table_name_22 (year INTEGER, result VARCHAR, extra VARCHAR, tournament VARCHAR, venue VARCHAR)