| 年度 | 实际值 |
|---|---|
| 1995 | 51.8 |
| 1996 | 52.1 |
| 1997 | 58.2 |
| 1998 | 52.9 |
| 1999 | 50.6 |
| 2000 | 54 |
| 2001 | 52.58 |
| 2002 | 53.41 |
| 2003 | 48.36 |
| 2004 | 49.88 |
| 2005 | 49.57 |
| 2006 | 53.12 |
| 2007 | 55.23 |
| 2008 | 57.9 |
| 2009 | |
| 2010 | 59.26 |
| 2011 | 63.31 |
| 2012 | 64.03 |
| 2013 | 63.74 |
| 2014 | 63.05 |
| 2015 | 61.57 |
| 2016 | 60.61 |
| 2017 | 51.54 |
| 2018 | 50.23 |