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_47 (air_date VARCHAR)
### Question:
What is the total number of ratings among the 18 to 49 group that was aired on January 7, 2009?
### Answer:
SELECT COUNT(18 AS _49) FROM table_name_47 WHERE air_date = "january 7, 2009"