| 年度 | 实际值 |
|---|---|
| 1992 | 19522 |
| 1993 | |
| 1994 | |
| 1995 | 21335 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 20996 |
| 2000 | 21190 |
| 2001 | 20308 |
| 2002 | 20957 |
| 2003 | 21054 |
| 2004 | 20060 |
| 2005 | 20192 |
| 2006 | 19925 |
| 2007 | 19838 |
| 2008 | 16864 |
| 2009 | 16679 |
| 2010 | 16823 |
| 2011 | 17351 |
| 2012 | 17540 |
| 2013 | 17739 |
| 2014 | 17597 |
| 2015 | 17732 |
| 2016 | 17996 |