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

### Instruction:
What is the total number of ratings among the 18 to 49 group that was aired on January 7, 2009?

### Inputs:
table_name: table, columns: ['Episode', 'Air Date', 'Timeslot (EST)', 'Season', 'Rating', 'Share', '18–49', 'Viewers (m)', 'Rank (#)']

### Response:
SELECT COUNT 18–49 FROM table WHERE Air Date = january 7, 2009