Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_71 (year INTEGER, mixed_doubles VARCHAR)
### Question:
What is the average year with Nathan Robertson Gail Emms in mixed doubles?
### Answer:
SELECT AVG(year) FROM table_name_71 WHERE mixed_doubles = "nathan robertson gail emms"