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 # | Episode # | Title | Written by | Directed by | Viewers | Original airdate |
| --- | --- | --- | --- | --- | --- | --- |
| 14.0 | 1.0 | The Hero's Standard | Michael Miller | Peter Andrikidis | 259000.0 | 20 April 2011 |
| 15.0 | 2.0 | Heart of Darkness | David Ogilvy | Peter Andrikidis | 243000.0 | 27 April 2011 |
| 16.0 | 3.0 | Jerusalem | Katherine Thomson | Peter Andrikidis | 222000.0 | 4 May 2011 |
| 17.0 | 4.0 | The Transit of Venus | Michael Miller | Peter Andrikidis | 178000.0 | 11 May 2011 |
| 18.0 | 5.0 | The Price of Salvation | Michelle Offen | Peter Andrikidis | 220000.0 | 18 May 2011 |
| 19.0 | 6.0 | Behold a Pale Horse | Vanessa Bates | Peter Andrikidis | 181000.0 | 25 May 2011 |
Question:
What was the original air date of the episode written by Michelle Offen?
Answer:
18 May 2011