| 年度 | 实际值 |
|---|---|
| 1993 | 27.4 |
| 1994 | |
| 1995 | 26.2 |
| 1996 | 25.1 |
| 1997 | 18.8 |
| 1998 | 18.8 |
| 1999 | 19.2 |
| 2000 | 19.8 |
| 2001 | 1.47333333333333 |
| 2002 | |
| 2003 | 29.17 |
| 2004 | 28.5 |
| 2005 | 31 |
| 2006 | 43.19 |
| 2007 | 45.35 |
| 2008 | 31.33 |
| 2009 | |
| 2010 | 36.59 |
| 2011 | 38.66 |
| 2012 | 39.81 |
| 2013 | 39.34 |
| 2014 | 40.11 |
| 2015 | 42.56 |
| 2016 | 41.63 |
| 2017 | 45.8 |
| 2018 | 45.8 |