| 年度 | 实际值 |
|---|---|
| 1993 | 32000 |
| 1994 | 32300 |
| 1995 | 31100 |
| 1996 | 30000 |
| 1997 | 35400 |
| 1998 | 35500 |
| 1999 | |
| 2000 | 34155 |
| 2001 | 32184 |
| 2002 | 34232 |
| 2003 | 34419 |
| 2004 | 32961 |
| 2005 | 32977 |
| 2006 | 32042 |
| 2007 | 31653 |
| 2008 | 32079 |
| 2009 | 30094 |
| 2010 | 28740 |
| 2011 | 23589 |
| 2012 | 23853 |
| 2013 | 20891 |
| 2014 | 19919 |
| 2015 | 20346 |
| 2016 | 20381 |
| 2017 | 20260 |