Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_12570759_2 ( written_by VARCHAR, us_viewers__millions_ VARCHAR )

### Question ###
How many episodes were watched by 12.72 million U.S. viewers?

### Accurate SQL ###

SELECT COUNT(written_by) FROM table_12570759_2 WHERE us_viewers__millions_ = "12.72"