| 年度 | 实际值 |
|---|---|
| 1995 | 51.3 |
| 1996 | 51.7 |
| 1997 | 51.67 |
| 1998 | 52.8 |
| 1999 | 53.1 |
| 2000 | 53.5 |
| 2001 | 52.83 |
| 2002 | 52.81 |
| 2003 | 53.24 |
| 2004 | 53.5 |
| 2005 | 57.77 |
| 2006 | 58.64 |
| 2007 | 59.07 |
| 2008 | 59.35 |
| 2009 | |
| 2010 | 60.16 |
| 2011 | 62.34 |
| 2012 | 62.22 |
| 2013 | 61.84 |
| 2014 | 61.98 |
| 2015 | 59.95 |
| 2016 | 58.48 |
| 2017 | |
| 2018 | 57.69 |