| 年度 | 实际值 |
|---|---|
| 1993 | 22.5 |
| 1994 | |
| 1995 | 22.5 |
| 1996 | 22.5 |
| 1997 | 23.2 |
| 1998 | 24.1 |
| 1999 | 24.1 |
| 2000 | 23.5 |
| 2001 | 1.74 |
| 2002 | |
| 2003 | 35.51 |
| 2004 | 41.41 |
| 2005 | 42 |
| 2006 | 38.62 |
| 2007 | 46 |
| 2008 | 26.19 |
| 2009 | |
| 2010 | 29.68 |
| 2011 | 49.27 |
| 2012 | 47.77 |
| 2013 | 46.12 |
| 2014 | 40.45 |
| 2015 | 40.48 |
| 2016 | 41.07 |
| 2017 | 41.4 |
| 2018 | 41.1 |