| 年度 | 实际值 |
|---|---|
| 1993 | 10.1 |
| 1994 | |
| 1995 | 10.8 |
| 1996 | 20.8 |
| 1997 | 16.5 |
| 1998 | 17.7 |
| 1999 | 16.3 |
| 2000 | 8.3 |
| 2001 | .54 |
| 2002 | |
| 2003 | 16.02 |
| 2004 | 16.71 |
| 2005 | 21 |
| 2006 | 29.63 |
| 2007 | 31.88 |
| 2008 | 33.35 |
| 2009 | |
| 2010 | 36.22 |
| 2011 | 41.54 |
| 2012 | 50.87 |
| 2013 | 32.51 |
| 2014 | 32.6 |
| 2015 | 33.61 |
| 2016 | 42.04 |
| 2017 | 30.22 |
| 2018 | 34.13 |