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:
| Year | Broadcast date | BBC One total viewing | BBC One Rank | BBC Two total viewing | BBC Two Rank |
| --- | --- | --- | --- | --- | --- |
| 1999.0 | 12 March | 6830000.0 | 20th | 3,130,000 | 13th |
| 2001.0 | 16 March | 8510000.0 | 8th | N/A | N/A |
| 2003.0 | 14 March | 11740000.0 | 4th | 6,010,000 | 1st |
| 2005.0 | 11 March | 10940000.0 | 4th | 4,720,000 | 1st |
| 2007.0 | 16 March | 9730000.0 | 2nd | 6,400,000 | 1st |
| 2009.0 | 13 March | 9840000.0 | 1st | 7,090,000 | 1st |
| 2011.0 | 18 March | 10260000.0 | 1st | 7,530,000 | 1st |
| 2013.0 | 15 March | 10280000.0 | 1st | 4,790,000 | 1st |
Question:
How many years did BBC One rank 20th?
Answer:
1.0