| 年度 | 实际值 |
|---|---|
| 1995 | 25.4 |
| 1996 | 13.7 |
| 1997 | 6.39 |
| 1998 | 7.1 |
| 1999 | 6.15 |
| 2000 | 14.1 |
| 2001 | 8.1 |
| 2002 | 10.1 |
| 2003 | 15.4 |
| 2004 | 14.8 |
| 2005 | 12.6 |
| 2006 | 13.1 |
| 2007 | 13.26161209 |
| 2008 | 10.818478437861 |
| 2009 | 10.3475977774561 |
| 2010 | 14.9 |
| 2011 | 12.9043164539142 |
| 2012 | 7.0952551227244 |
| 2013 | 7.5 |
| 2014 | 9.8 |
| 2015 | 7.83475087701882 |
| 2016 | |
| 2017 | 7.7 |
| 2018 | 5.17 |