| 年度 | 实际值 |
|---|---|
| 1995 | 51.7 |
| 1996 | 51.3 |
| 1997 | 54.1 |
| 1998 | 52.2 |
| 1999 | 51.6 |
| 2000 | 52.4 |
| 2001 | 52.31 |
| 2002 | 53.27 |
| 2003 | 55.44 |
| 2004 | 58.16 |
| 2005 | 60.13 |
| 2006 | 61.67 |
| 2007 | 62.68 |
| 2008 | 65.22 |
| 2009 | |
| 2010 | 66.33 |
| 2011 | 65.59 |
| 2012 | 60.89 |
| 2013 | 58.23 |
| 2014 | 53.72 |
| 2015 | 52.19 |
| 2016 | 49.04 |
| 2017 | |
| 2018 | 47.74 |