| 年度 | 实际值 |
|---|---|
| 1992 | 28457 |
| 1993 | |
| 1994 | |
| 1995 | 28659 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 24048 |
| 2000 | 24450 |
| 2001 | 23645 |
| 2002 | 22641 |
| 2003 | 20778 |
| 2004 | 21242 |
| 2005 | 21770 |
| 2006 | 21807 |
| 2007 | 21590 |
| 2008 | 19461 |
| 2009 | 20472 |
| 2010 | 20333 |
| 2011 | 20650 |
| 2012 | 20741 |
| 2013 | 20810 |
| 2014 | 20845 |
| 2015 | 20677 |
| 2016 | 20733 |