| 年度 | 实际值 |
|---|---|
| 1992 | 25.9 |
| 1993 | |
| 1994 | |
| 1995 | 26.5 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 26.5 |
| 2000 | 263921 |
| 2001 | 262575 |
| 2002 | 20.7353 |
| 2003 | 25.0472 |
| 2004 | 25.0772 |
| 2005 | 25.0797 |
| 2006 | 25.32 |
| 2007 | 25.52 |
| 2008 | 25.71 |
| 2009 | 24.8877 |
| 2010 | 25.0401 |
| 2011 | 25.1776 |
| 2012 | 25.07 |
| 2013 | 25.31 |
| 2014 | 25.59 |
| 2015 | 23.26 |
| 2016 | 23.38 |