Zobrazení grafu: týden | měsíc | půl roku | rok | 5 let | 15 let
| Rok | Maximální | Minimální | Průměr |
|---|---|---|---|
| 1997 | 10.317 | 9.191 | 9.686 |
| 1998 | 10.195 | 8.132 | 9.250 |
| 1999 | 9.259 | 8.081 | 8.726 |
| 2000 | 9.275 | 8.475 | 8.882 |
| 2001 | 10.125 | 8.639 | 9.294 |
| 2002 | 9.177 | 6.947 | 8.019 |
| 2003 | 7.950 | 6.812 | 7.250 |
| 2004 | 7.536 | 6.615 | 7.050 |
| 2005 | 7.665 | 7.126 | 7.405 |
| 2006 | 7.671 | 6.936 | 7.278 |
| 2007 | 7.662 | 7.105 | 7.338 |
| 2008 | 7.471 | 6.372 | 7.115 |
| 2009 | 6.572 | 5.754 | 6.115 |
| 2010 | 6.649 | 6.118 | 6.334 |
| 2011 | 6.409 | 5.510 | 5.981 |
| 2012 | 6.049 | 5.700 | 5.932 |