Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Series | Start date | End date | Episodes | Average viewers (millions) |
| --- | --- | --- | --- | --- |
| 1.0 | 22 August 2009 | 3 October 2009 | 7.0 | 5.09 |
| 2.0 | 19 September 2010 | 2 January 2011 | 12.0 | 4.95 |
| 3.0 | 3 April 2011 | 11 June 2011 | 9.0 | 3.72 |
| 4.0 | 30 October 2011 | 31 December 2011 | 9.0 | 4.2 |
| 5.0 | 14 April 2012 | 23 December 2012 | 9.0 | 3.26 |
| 6.0 | 2 March 2013 | 30 June 2013 | 13.0 | 3.66 |
Question:
What series had an average of 3.72 million people watching it?
Answer:
3.0