| 年度 | 实际值 |
|---|---|
| 1995 | 59.9 |
| 1996 | 60.7 |
| 1997 | 45.65 |
| 1998 | 58.6 |
| 1999 | 54 |
| 2000 | 57.2 |
| 2001 | 57.48 |
| 2002 | 58.2 |
| 2003 | 60.28 |
| 2004 | 64.98 |
| 2005 | 60.27 |
| 2006 | 57.21 |
| 2007 | 57.42 |
| 2008 | 56.57 |
| 2009 | |
| 2010 | 56.02 |
| 2011 | 59.18 |
| 2012 | 55.93 |
| 2013 | 53.49 |
| 2014 | 52.69 |
| 2015 | 51.67 |
| 2016 | 48.47 |
| 2017 | 47.97 |
| 2018 | 47.23 |