| 年度 | 实际值 |
|---|---|
| 1995 | 39.5 |
| 1996 | 41.3 |
| 1997 | 42.36 |
| 1998 | 41.7 |
| 1999 | 42.6 |
| 2000 | 38.4 |
| 2001 | 38.22 |
| 2002 | 38.47 |
| 2003 | 39.37 |
| 2004 | 38.75 |
| 2005 | 38.58 |
| 2006 | 41.74 |
| 2007 | 44.49 |
| 2008 | 48.62 |
| 2009 | |
| 2010 | 56.48 |
| 2011 | 59.74 |
| 2012 | 60.56 |
| 2013 | 60.01 |
| 2014 | 60.25 |
| 2015 | 59.61 |
| 2016 | 59.1 |
| 2017 | |
| 2018 | 52.09 |