| 年度 | 实际值 |
|---|---|
| 1995 | 40.9 |
| 1996 | 45.7 |
| 1997 | 48.75 |
| 1998 | 49.9 |
| 1999 | 50.8 |
| 2000 | 52.2 |
| 2001 | 52.46 |
| 2002 | 52.87 |
| 2003 | 54.58 |
| 2004 | 57.05 |
| 2005 | 57.3 |
| 2006 | 57.95 |
| 2007 | 56.48 |
| 2008 | 57.06 |
| 2009 | |
| 2010 | 55.61 |
| 2011 | 55.52 |
| 2012 | 54.15 |
| 2013 | 52.38 |
| 2014 | 47.36 |
| 2015 | 44.97 |
| 2016 | 46.86 |
| 2017 | |
| 2018 | 40.77 |