| 年度 | 实际值 |
|---|---|
| 1995 | 48.4 |
| 1996 | 48.6 |
| 1997 | 51.61 |
| 1998 | 51.2 |
| 1999 | 51.9 |
| 2000 | 51.8 |
| 2001 | 51.37 |
| 2002 | 51.84 |
| 2003 | 53.57 |
| 2004 | 56.7 |
| 2005 | 59.53 |
| 2006 | 60.78 |
| 2007 | 60.97 |
| 2008 | 60.89 |
| 2009 | |
| 2010 | 58.89 |
| 2011 | 57.69 |
| 2012 | 56.52 |
| 2013 | 54.78 |
| 2014 | 52.98 |
| 2015 | 51.56 |
| 2016 | 49.98 |
| 2017 | |
| 2018 | 49.08 |