| 年度 | 实际值 |
|---|---|
| 1995 | 21.8 |
| 1996 | 24.1 |
| 1997 | 34.4 |
| 1998 | 30.1 |
| 1999 | 35.6 |
| 2000 | 34.8 |
| 2001 | 34.01 |
| 2002 | 36.21 |
| 2003 | 35.57 |
| 2004 | 34.77 |
| 2005 | 42 |
| 2006 | 37.45 |
| 2007 | 43.57 |
| 2008 | 37.72 |
| 2009 | |
| 2010 | 34.44 |
| 2011 | 35.12 |
| 2012 | 34.64 |
| 2013 | 35.91 |
| 2014 | 37.36 |
| 2015 | 39.55 |
| 2016 | 40.94 |
| 2017 | 41.97 |
| 2018 | 43.09 |