| Year of recruitment | Effective | Percentage |
| 2008 | 2 | 3.6 |
| 2009 | 1 | 1.8 |
| 2010 | 3 | 5.3 |
| 2011 | 3 | 5.3 |
| 2012 | 4 | 7.0 |
| 2013 | 4 | 7.0 |
| 2014 | 5 | 8.8 |
| 2015 | 4 | 7.0 |
| 2016 | 7 | 12.3 |
| 2017 | 9 | 15.8 |
| 2018 | 10 | 17.5 |
| 2019 | 5 | 8.8 |
| total | 57 | 100 |