| Rok | Maximální | Minimální | Průměr |
|---|---|---|---|
| 2004 | 17.062 | 15.541 | 16.334 |
| 2005 | 15.622 | 14.758 | 15.226 |
| 2006 | 14.848 | 14.019 | 14.488 |
| 2007 | 14.711 | 13.293 | 14.190 |
| 2008 | 13.770 | 11.743 | 12.765 |
| 2009 | 15.067 | 12.824 | 13.494 |
| 2010 | 13.532 | 12.476 | 12.938 |
| 2011 | 13.307 | 12.276 | 12.572 |
| 2012 | 13.248 | 12.812 | 13.025 |