| 年度 | 实际值 |
|---|---|
| 1993 | 15.3 |
| 1994 | |
| 1995 | 33.1 |
| 1996 | 37.8 |
| 1997 | 38.9 |
| 1998 | 38.5 |
| 1999 | 36.5 |
| 2000 | 38 |
| 2001 | 2.75333333333333 |
| 2002 | |
| 2003 | 43.28 |
| 2004 | 41.03 |
| 2005 | 40 |
| 2006 | 39.78 |
| 2007 | 41.17 |
| 2008 | 45.33 |
| 2009 | |
| 2010 | 45.33 |
| 2011 | 21.35 |
| 2012 | 15.02 |
| 2013 | 39.28 |
| 2014 | 38.85 |
| 2015 | 38.05 |
| 2016 | 39.05 |
| 2017 | 40.65 |
| 2018 | 40.59 |