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:
| Episode No. | Series No. | Title | Directed by | Written by | Viewers (millions) | Original airdate |
| --- | --- | --- | --- | --- | --- | --- |
| 16.0 | 1.0 | "The Apple Doesn't Fall" | Ben Bolt | Richard Stoneman | 8.10 | 24September2007 |
| 17.0 | 2.0 | "Movement" | Ben Bolt | Nick Vivan | 8.58 | 1October2007 |
| 18.0 | 3.0 | "City Slickers" | Ben Bolt | Richard Stoneman | 8.84 | 8October2007 |
| 19.0 | 4.0 | "The Admirer" | Ben Bolt | Jack Lothian | 8.81 | 15October2007 |
| 20.0 | 5.0 | "The Holly Bears a Prickle" | Ben Bolt | Ben Bolt | 9.21 | 22October2007 |
| 21.0 | 6.0 | "Nowt So Queer" | Ben Bolt | Keith Temple | 9.92 | 29October2007 |
Question:
How many million viewers watched episode number 20?
Answer:
9.21