| 年度 | 实际值 |
|---|---|
| 1995 | 43 |
| 1996 | 41.9 |
| 1997 | 41.62 |
| 1998 | 41.5 |
| 1999 | 39.4 |
| 2000 | 40.6 |
| 2001 | 36.97 |
| 2002 | 36.57 |
| 2003 | 39.73 |
| 2004 | 42.6 |
| 2005 | 46.19 |
| 2006 | 46.06 |
| 2007 | 46.41 |
| 2008 | 44.08 |
| 2009 | |
| 2010 | 49.23 |
| 2011 | 52.98 |
| 2012 | 52.93 |
| 2013 | 55.09 |
| 2014 | 52.77 |
| 2015 | 50.18 |
| 2016 | 46.03 |
| 2017 | |
| 2018 | 41.99 |