| 年度 | 实际值 |
|---|---|
| 1993 | 11.7 |
| 1994 | |
| 1995 | 12.3 |
| 1996 | 6.7 |
| 1997 | |
| 1998 | 6.1 |
| 1999 | 5.4 |
| 2000 | 12.5 |
| 2001 | 1.5 |
| 2002 | |
| 2003 | 7.76 |
| 2004 | 19.72 |
| 2005 | 10 |
| 2006 | 26.43 |
| 2007 | 25.52 |
| 2008 | 26.64 |
| 2009 | |
| 2010 | 31.79 |
| 2011 | 47.17 |
| 2012 | 39.51 |
| 2013 | 39.06 |
| 2014 | 40.7 |
| 2015 | 22.46 |
| 2016 | 40.93 |
| 2017 | 40.61 |
| 2018 | 41.04 |