| 年度 | 实际值 |
|---|---|
| 1995 | 62.7 |
| 1996 | 60.2 |
| 1997 | 51.45 |
| 1998 | 61.8 |
| 1999 | 60.5 |
| 2000 | 60.3 |
| 2001 | 57.21 |
| 2002 | 57.56 |
| 2003 | 55.22 |
| 2004 | 55.25 |
| 2005 | 56.58 |
| 2006 | 56.28 |
| 2007 | 61.14 |
| 2008 | 62.42 |
| 2009 | |
| 2010 | 61.34 |
| 2011 | 64.68 |
| 2012 | 63.22 |
| 2013 | 61.85 |
| 2014 | 60.92 |
| 2015 | 58.33 |
| 2016 | 52.33 |
| 2017 | 45.01 |
| 2018 | 42.97 |