Zobrazení grafu: týden | měsíc | půl roku | rok | 5 let | 15 let
| Rok | Maximální | Minimální | Průměr |
|---|---|---|---|
| 1991 | 23.210 | 20.280 | 21.920 |
| 1992 | 23.257 | 21.400 | 22.323 |
| 1993 | 29.387 | 22.977 | 26.310 |
| 1994 | 29.125 | 26.584 | 28.156 |
| 1995 | 31.695 | 25.426 | 28.361 |
| 1996 | 26.591 | 23.503 | 24.992 |
| 1997 | 29.954 | 22.398 | 26.263 |
| 1998 | 28.018 | 21.118 | 24.734 |
| 1999 | 35.281 | 26.143 | 30.494 |
| 2000 | 39.285 | 32.077 | 35.853 |
| 2001 | 33.890 | 27.206 | 31.348 |
| 2002 | 28.143 | 24.642 | 26.106 |
| 2003 | 25.829 | 22.325 | 24.335 |
| 2004 | 25.889 | 21.554 | 23.756 |
| 2005 | 22.947 | 20.214 | 21.766 |
| 2006 | 20.934 | 17.522 | 19.417 |
| 2007 | 18.675 | 15.802 | 17.223 |
| 2008 | 22.037 | 13.540 | 16.633 |
| 2009 | 25.368 | 18.578 | 20.281 |
| 2010 | 23.817 | 19.520 | 21.769 |
| 2011 | 25.841 | 19.886 | 22.215 |
| 2012 | 26.394 | 24.721 | 25.611 |