Zobrazení grafu: týden | měsíc | půl roku | rok | 5 let | 15 let
| Rok | Maximální | Minimální | Průměr |
|---|---|---|---|
| 1991 | 21.860 | 19.870 | 20.592 |
| 1992 | 21.756 | 18.950 | 20.155 |
| 1993 | 20.628 | 18.892 | 19.732 |
| 1994 | 21.986 | 20.201 | 21.065 |
| 1995 | 23.164 | 21.274 | 22.455 |
| 1996 | 23.115 | 20.215 | 22.005 |
| 1997 | 24.632 | 19.185 | 21.857 |
| 1998 | 24.399 | 20.495 | 22.262 |
| 1999 | 24.251 | 21.539 | 23.042 |
| 2000 | 23.815 | 22.041 | 22.857 |
| 2001 | 23.665 | 21.321 | 22.552 |
| 2002 | 22.080 | 19.682 | 21.002 |
| 2003 | 21.868 | 20.172 | 20.945 |
| 2004 | 21.334 | 19.688 | 20.661 |
| 2005 | 19.851 | 18.562 | 19.233 |
| 2006 | 18.719 | 17.093 | 18.013 |
| 2007 | 17.618 | 15.639 | 16.898 |
| 2008 | 18.132 | 14.163 | 15.748 |
| 2009 | 19.893 | 16.525 | 17.479 |
| 2010 | 20.267 | 17.428 | 18.320 |
| 2011 | 23.039 | 18.407 | 19.977 |
| 2012 | 21.315 | 20.804 | 21.048 |