| 年度 | 实际值 |
|---|---|
| 1995 | 44.4 |
| 1996 | 44.6 |
| 1997 | 68.03 |
| 1998 | 40.6 |
| 1999 | 37.1 |
| 2000 | 34.6 |
| 2001 | 34.01 |
| 2002 | 35.22 |
| 2003 | 39.21 |
| 2004 | 41.14 |
| 2005 | 36.26 |
| 2006 | 35.45 |
| 2007 | 32.07 |
| 2008 | 35.55 |
| 2009 | |
| 2010 | 33.04 |
| 2011 | 41.12 |
| 2012 | 44.49 |
| 2013 | 45.37 |
| 2014 | 43.56 |
| 2015 | 43.39 |
| 2016 | 41.42 |
| 2017 | 39.33 |
| 2018 | 39.36 |