Zobrazení grafu: týden | měsíc | půl roku | rok | 5 let | 15 let
| Rok | Maximální | Minimální | Průměr |
|---|---|---|---|
| 1997 | 18.202 | 16.139 | 16.995 |
| 1998 | 17.442 | 13.259 | 15.077 |
| 1999 | 15.345 | 13.791 | 14.584 |
| 2000 | 14.333 | 12.936 | 13.700 |
| 2001 | 13.969 | 12.813 | 13.277 |
| 2002 | 13.395 | 11.493 | 12.687 |
| 2003 | 13.606 | 11.804 | 12.571 |
| 2004 | 13.215 | 12.053 | 12.673 |
| 2005 | 12.394 | 11.339 | 12.008 |
| 2006 | 11.556 | 10.056 | 10.740 |
| 2007 | 11.707 | 10.319 | 11.047 |
| 2008 | 10.486 | 9.050 | 9.929 |
| 2009 | 10.112 | 8.823 | 9.431 |
| 2010 | 9.818 | 8.552 | 9.198 |
| 2011 | 9.275 | 8.090 | 8.824 |
| 2012 | 8.594 | 8.053 | 8.344 |