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 No. | Episode No. | Title | Directed by | Written by | UK Ratings (BBC2 Rank) | Original air date |
| --- | --- | --- | --- | --- | --- | --- |
| 7.0 | 1.0 | "The Mysteries of the Isles" | Various | n/a | 2.88m (2) | 13May2012 |
| 7.0 | 2.0 | "Life Beyond the Edge" | Various | n/a | 2.54m (2) | 20May2012 |
| 7.0 | 3.0 | "The Hidden History of Harbours" | Various | n/a | 1.94m (7) | 27May2012 |
| 7.0 | 4.0 | "Peril from the Seas" | Various | n/a | 1.82m (10) | 3June2012 |
| 7.0 | 5.0 | "The Riddle of the Tides" | Various | n/a | 1.99m (8) | 10June2012 |
Question:
Name the least series number
Answer:
7.0