| 年度 | 实际值 |
|---|---|
| 1995 | 41.6 |
| 1996 | 39.7 |
| 1997 | 28.03 |
| 1998 | 28.2 |
| 1999 | 28.1 |
| 2000 | 30.2 |
| 2001 | 31.87 |
| 2002 | 32.85 |
| 2003 | 39.12 |
| 2004 | 38.24 |
| 2005 | 39.4 |
| 2006 | 40.38 |
| 2007 | 42.07 |
| 2008 | 44.67 |
| 2009 | |
| 2010 | 46.52 |
| 2011 | 47.61 |
| 2012 | 46.75 |
| 2013 | 46.81 |
| 2014 | 43.33 |
| 2015 | 41.79 |
| 2016 | 41.42 |
| 2017 | |
| 2018 | 41.34 |