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:
| Team | Outgoing head coach | Manner of departure | Date of vacancy | Position in table | Incoming head coach | Date of appointment |
| --- | --- | --- | --- | --- | --- | --- |
| União de Leiria | Lito Vidigal | Sacked | 7 July 2010 | Off-season | Pedro Caixinha | 10 July 2010 |
| Marítimo | Mitchell van der Gaag | Sacked | 14 September 2010 | 15th | Pedro Martins | 14 September 2010 |
| Naval 1º de Maio | Victor Zvunka | Sacked | 27 September 2010 | 14th | Rogério Gonçalves | 6 October 2010 |
| Académica | Jorge Costa | Resigned | 21 December 2010 | 9th | José Guilherme | 27 December 2010 |
| Naval 1º de Maio | Rogério Gonçalves | Sacked | 19 December 2010 | 16th | Carlos Mozer | 30 December 2010 |
| Portimonense | Litos | Sacked | 28 December 2011 | 16th | Carlos Azenha | 29 December 2010 |
| Académica | José Guilherme | Resigned | 20 February 2011 | 13th | Ulisses Morais | 22 February 2011 |
| Sporting | Paulo Sérgio | Resigned | 26 February 2011 | 3rd | José Couceiro | 26 February 2011 |
| Beira-Mar | Leonardo Jardim | Resigned | 28 February 2011 | 10th | Rui Bento | 1 March 2011 |
| Vitória de Setúbal | Manuel Fernandes | Sacked | 1 March 2011 | 14th | Bruno Ribeiro | 1 March 2011 |
Question:
If the position in table is 10th, and the manner of departure was resigned, what was the date of vacancy?
Answer:
28 February 2011