| 年度 | 实际值 |
|---|---|
| 1993 | 23.9 |
| 1994 | |
| 1995 | 23.6 |
| 1996 | 26.3 |
| 1997 | 26.6 |
| 1998 | 28.4 |
| 1999 | 31.1 |
| 2000 | 33 |
| 2001 | 2.1 |
| 2002 | |
| 2003 | 37.46 |
| 2004 | 40.96 |
| 2005 | 42 |
| 2006 | 41.83 |
| 2007 | 42.05 |
| 2008 | 41.8 |
| 2009 | |
| 2010 | 40.36 |
| 2011 | 40.77 |
| 2012 | 41.34 |
| 2013 | 42.05 |
| 2014 | 42.55 |
| 2015 | 42.71 |
| 2016 | 43.2 |
| 2017 | 43.54 |
| 2018 | 44 |