| 年度 | 实际值 |
|---|---|
| 1995 | 20.3 |
| 1996 | 22.6 |
| 1997 | 46.92 |
| 1998 | 39.1 |
| 1999 | 41.5 |
| 2000 | 42.4 |
| 2001 | 43.66 |
| 2002 | 34.43 |
| 2003 | 33.66 |
| 2004 | 33.2 |
| 2005 | 30.59 |
| 2006 | 29.61 |
| 2007 | 30.8 |
| 2008 | 29.57 |
| 2009 | |
| 2010 | 33.37 |
| 2011 | 30.96 |
| 2012 | 31.38 |
| 2013 | 34 |
| 2014 | 34 |
| 2015 | 34.98 |
| 2016 | 36.17 |
| 2017 | 40.26 |
| 2018 | 41.25 |