| 年度 | 实际值 |
|---|---|
| 1992 | 24.14 |
| 1993 | 25.55 |
| 1994 | 27.02 |
| 1995 | 28.01 |
| 1996 | 28.99 |
| 1997 | 32.27 |
| 1998 | 32.65 |
| 1999 | 32.81 |
| 2000 | 33.43 |
| 2001 | 30.7549 |
| 2002 | 30.6357 |
| 2003 | 30.7129 |
| 2004 | 30.609 |
| 2005 | 30.7352 |
| 2006 | 30.957 |
| 2007 | 31.0836 |
| 2008 | 31.2864 |
| 2009 | 31.4861 |
| 2010 | 31.49 |
| 2011 | 32 |
| 2012 | 32.1 |
| 2013 | 96.7 |
| 2014 | 95.8 |
| 2015 | 96.77 |
| 2016 | 97 |
| 2017 | 97 |
| 2018 | 97 |