Zobrazení grafu: týden | měsíc | půl roku | rok | 5 let | 15 let
| Rok | Maximální | Minimální | Průměr |
|---|---|---|---|
| 1991 | 27.580 | 23.250 | 25.745 |
| 1992 | 25.020 | 21.283 | 23.425 |
| 1993 | 23.519 | 21.344 | 22.614 |
| 1994 | 23.073 | 19.971 | 21.088 |
| 1995 | 20.287 | 18.226 | 19.339 |
| 1996 | 20.494 | 19.032 | 19.910 |
| 1997 | 25.344 | 19.686 | 22.894 |
| 1998 | 25.193 | 18.358 | 21.834 |
| 1999 | 24.784 | 19.371 | 23.268 |
| 2000 | 28.252 | 23.947 | 25.990 |
| 2001 | 26.480 | 22.245 | 24.577 |
| 2002 | 23.338 | 18.929 | 20.828 |
| 2003 | 21.744 | 18.975 | 20.141 |
| 2004 | 20.725 | 18.370 | 19.743 |
| 2005 | 21.278 | 18.077 | 19.785 |
| 2006 | 21.144 | 17.991 | 19.914 |
| 2007 | 20.186 | 17.522 | 18.923 |
| 2008 | 18.421 | 14.421 | 16.022 |
| 2009 | 18.471 | 15.705 | 16.646 |
| 2010 | 20.789 | 17.092 | 18.540 |
| 2011 | 19.643 | 16.878 | 17.876 |
| 2012 | 19.983 | 19.002 | 19.460 |