| 年度 | 实际值 |
|---|---|
| 1995 | 53.2 |
| 1996 | 49.2 |
| 1997 | 49.34 |
| 1998 | 45.6 |
| 1999 | 44.8 |
| 2000 | 47.8 |
| 2001 | 47.75 |
| 2002 | 50.12 |
| 2003 | 53.85 |
| 2004 | 56.51 |
| 2005 | 57.5 |
| 2006 | 58.4 |
| 2007 | 60.38 |
| 2008 | 62.49 |
| 2009 | |
| 2010 | 61.52 |
| 2011 | 58.75 |
| 2012 | 57.49 |
| 2013 | 57.08 |
| 2014 | 52.36 |
| 2015 | 50.55 |
| 2016 | 47.84 |
| 2017 | |
| 2018 | 46.15 |