| 年度 | 实际值 |
|---|---|
| 1993 | 5.1 |
| 1994 | |
| 1995 | 5.9 |
| 1996 | 8.5 |
| 1997 | 8.5 |
| 1998 | 8.6 |
| 1999 | 8.8 |
| 2000 | 9.1 |
| 2001 | .62 |
| 2002 | |
| 2003 | 11.35 |
| 2004 | 11.35 |
| 2005 | 11 |
| 2006 | 18 |
| 2007 | 18.21 |
| 2008 | 22.37 |
| 2009 | |
| 2010 | 25.21 |
| 2011 | 32.58 |
| 2012 | 29.21 |
| 2013 | 30.16 |
| 2014 | 30.84 |
| 2015 | 42.68 |
| 2016 | 40.55 |
| 2017 | 40.5 |
| 2018 | 40.5 |