| 年度 | 实际值 |
|---|---|
| 1995 | 34.5 |
| 1996 | 32.6 |
| 1997 | 33.07 |
| 1998 | 38.9 |
| 1999 | 44 |
| 2000 | 45.3 |
| 2001 | 46.24 |
| 2002 | 46.31 |
| 2003 | 46.24 |
| 2004 | 43.73 |
| 2005 | 46.15 |
| 2006 | 45.93 |
| 2007 | 42.69 |
| 2008 | 39.53 |
| 2009 | |
| 2010 | 38.09 |
| 2011 | 34.34 |
| 2012 | 33.01 |
| 2013 | 34.59 |
| 2014 | 35.84 |
| 2015 | 36.51 |
| 2016 | 37.7 |
| 2017 | |
| 2018 | 40.06 |