| 年度 | 实际值 |
|---|---|
| 1995 | 44.5 |
| 1996 | 42.7 |
| 1997 | 44.06 |
| 1998 | 43.9 |
| 1999 | 43.8 |
| 2000 | 44.2 |
| 2001 | 43.86 |
| 2002 | 43.94 |
| 2003 | 47.32 |
| 2004 | 49.48 |
| 2005 | 43.49 |
| 2006 | 45.21 |
| 2007 | 48.3 |
| 2008 | 50.1 |
| 2009 | |
| 2010 | 50.42 |
| 2011 | 51.17 |
| 2012 | 51.24 |
| 2013 | 51.67 |
| 2014 | 49.88 |
| 2015 | 47.77 |
| 2016 | 38.79 |
| 2017 | |
| 2018 | 37.77 |