| 年度 | 实际值 |
|---|---|
| 1995 | 57.5 |
| 1996 | 56.4 |
| 1997 | 57.47 |
| 1998 | 55.4 |
| 1999 | 56 |
| 2000 | 56.5 |
| 2001 | 56.81 |
| 2002 | 58.02 |
| 2003 | 55.1 |
| 2004 | 55.22 |
| 2005 | 45.96 |
| 2006 | 48.23 |
| 2007 | 48.67 |
| 2008 | 50.5 |
| 2009 | |
| 2010 | 51.43 |
| 2011 | 54.26 |
| 2012 | 53.87 |
| 2013 | 53.36 |
| 2014 | 53.62 |
| 2015 | 51.16 |
| 2016 | 47.66 |
| 2017 | 47.33 |
| 2018 | 43.24 |