| 年度 | 实际值 |
|---|---|
| 1995 | 39.8 |
| 1996 | 36 |
| 1997 | 56.71 |
| 1998 | 33.6 |
| 1999 | 36.1 |
| 2000 | 38.5 |
| 2001 | 38.17 |
| 2002 | 40.43 |
| 2003 | 44.22 |
| 2004 | 44.9 |
| 2005 | 40.28 |
| 2006 | 41.6 |
| 2007 | 42.87 |
| 2008 | 45.36 |
| 2009 | |
| 2010 | 42.5 |
| 2011 | 44.98 |
| 2012 | 44.78 |
| 2013 | 44.48 |
| 2014 | 42.18 |
| 2015 | 41.26 |
| 2016 | 41.57 |
| 2017 | 34.21 |
| 2018 | 33.78 |