| Year | Number | Percentage (%) |
| 2008 | 2 | 10 |
| 2009 | 6 | 30 |
| 2010 | 4 | 20 |
| 2011 | 5 | 25 |
| 2012 | 1 | 5 |
| 2013 | 0 | 0 |
| 2014 | 1 | 5 |
| 2015 | 1 | 5 |