| 年度 | 实际值 |
|---|---|
| 1995 | 41.4 |
| 1996 | 36.9 |
| 1997 | 15.98 |
| 1998 | 41.5 |
| 1999 | 43 |
| 2000 | 41.3 |
| 2001 | 45.12 |
| 2002 | 40.37 |
| 2003 | 40.37 |
| 2004 | 38.22 |
| 2005 | 31.33 |
| 2006 | 32.17 |
| 2007 | 30.72 |
| 2008 | 33.04 |
| 2009 | |
| 2010 | 38.76 |
| 2011 | 41.93 |
| 2012 | 40.52 |
| 2013 | 42.57 |
| 2014 | 43.19 |
| 2015 | 44.51 |
| 2016 | 46.89 |
| 2017 | 42.45 |
| 2018 | 38.78 |