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 | First Air Date | Rating (18–49) | Share (18–49) | Viewers (millions) | Rank (timeslot) | Rank (night) |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | January 4, 2010 | 3.3 | 8.0 | 9.50 | N/A | N/A |
| 2.0 | January 11, 2010 | 3.6 | 9.0 | 10.50 | N/A | N/A |
| 3.0 | January 18, 2010 | 3.8 | 9.0 | 10.66 | N/A | N/A |
| 4.0 | January 25, 2010 | 3.9 | 10.0 | 11.47 | N/A | N/A |
| 5.0 | February 1, 2010 | 4.1 | 10.0 | 11.73 | N7A | N/A |
| 6.0 | February 8, 2010 | 4.1 | 10.0 | 12.35 | N/A | N/A |
| 7.0 | February 15, 2010 | 4.1 | 10.0 | 11.53 | N/A | N/A |
| 8.0 | February 22, 2010 | 3.9 | 10.0 | 11.27 | N/A | N/A |
| 9.0 | March 1, 2010 | 5.3 | 14.0 | 15.15 | N/A | N/A |
Question:
what episode number had 11.73 million viewers? 
Answer:
5.0