| 年度 | 实际值 |
|---|---|
| 1995 | 53.5 |
| 1996 | 56.5 |
| 1997 | 60.9 |
| 1998 | 55.3 |
| 1999 | 54.4 |
| 2000 | 54.2 |
| 2001 | 53.13 |
| 2002 | 52.81 |
| 2003 | 57.84 |
| 2004 | 56.81 |
| 2005 | 56.75 |
| 2006 | 56.29 |
| 2007 | 55.8 |
| 2008 | 53.92 |
| 2009 | |
| 2010 | 52.93 |
| 2011 | 51.57 |
| 2012 | 50.34 |
| 2013 | 49.35 |
| 2014 | 45.81 |
| 2015 | 44.9 |
| 2016 | 41.19 |
| 2017 | 41.33 |
| 2018 | 42.27 |