| 年度 | 实际值 |
|---|---|
| 1995 | 56.4 |
| 1996 | 53.3 |
| 1997 | 62.2 |
| 1998 | 49.1 |
| 1999 | 49.4 |
| 2000 | 50.7 |
| 2001 | 50.38 |
| 2002 | 50.02 |
| 2003 | 44.42 |
| 2004 | 46.84 |
| 2005 | 41.87 |
| 2006 | 41.55 |
| 2007 | 41.13 |
| 2008 | 40.39 |
| 2009 | |
| 2010 | 43.17 |
| 2011 | 45.2 |
| 2012 | 39.78 |
| 2013 | 38.25 |
| 2014 | 27.63 |
| 2015 | 20.94 |
| 2016 | 22.6 |
| 2017 | 25.26 |
| 2018 | 22.71 |