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_24168 ( "Episode" text, "Broadcast date" text, "Run time" text, "Viewers (in millions)" text, "Archive" text )

### Question ###
what is all the broadcast date when viewers were 8.4 millions

### Accurate SQL ###

SELECT COUNT("Broadcast date") FROM table_24168 WHERE "Viewers (in millions)" = '8.4'