| 年度 | 实际值 |
|---|---|
| 1992 | 7.7 |
| 1993 | 8.3 |
| 1994 | |
| 1995 | 4.49 |
| 1996 | 2.51 |
| 1997 | 3.55 |
| 1998 | 4.76 |
| 1999 | 5.05 |
| 2000 | 6.8 |
| 2001 | 4.04 |
| 2002 | 5.44 |
| 2003 | 6.2 |
| 2004 | 5.55 |
| 2005 | 7.64 |
| 2006 | 9.61 |
| 2007 | 11.25 |
| 2008 | 9.89 |
| 2009 | |
| 2010 | 15.17 |
| 2011 | 6.4 |
| 2012 | 13.8 |
| 2013 | 14.5 |
| 2014 | 19.4 |
| 2015 | 10.92 |
| 2016 | 12.6 |
| 2017 | -0.25 |
| 2018 | 8.93 |