| 年度 | 实际值 |
|---|---|
| 1992 | 29.03 |
| 1993 | 29.27 |
| 1994 | 29.52 |
| 1995 | 29.83 |
| 1996 | 30.23 |
| 1997 | |
| 1998 | |
| 1999 | |
| 2000 | |
| 2001 | |
| 2002 | 31.23 |
| 2003 | 30.92 |
| 2004 | 31.09 |
| 2005 | 31.31 |
| 2006 | 31.76 |
| 2007 | 32.17 |
| 2008 | 32.69 |
| 2009 | |
| 2010 | 33.12 |
| 2011 | 33.8 |
| 2012 | 34.8 |
| 2013 | 33.5 |
| 2014 | 33.8 |
| 2015 | 34.13 |
| 2016 | 34 |
| 2017 | 101 |
| 2018 | 102 |