| 年度 | 实际值 |
|---|---|
| 1995 | 60.1 |
| 1996 | 56.9 |
| 1997 | 64.17 |
| 1998 | 52.7 |
| 1999 | 51 |
| 2000 | 59.8 |
| 2001 | 58.24 |
| 2002 | 52.91 |
| 2003 | 46.22 |
| 2004 | 52.13 |
| 2005 | 49.49 |
| 2006 | 58.86 |
| 2007 | 60.13 |
| 2008 | 61.06 |
| 2009 | |
| 2010 | 51.42 |
| 2011 | 56.1 |
| 2012 | 52.24 |
| 2013 | 57.71 |
| 2014 | 53.12 |
| 2015 | 50.39 |
| 2016 | 49.05 |
| 2017 | 49.83 |
| 2018 | 46.19 |