| 年度 | 实际值 |
|---|---|
| 1995 | 33.3 |
| 1996 | 35.6 |
| 1997 | 29.28 |
| 1998 | 40.4 |
| 1999 | |
| 2000 | 40.1 |
| 2001 | 40.88 |
| 2002 | 40.05 |
| 2003 | 36.36 |
| 2004 | 34.38 |
| 2005 | 32.91 |
| 2006 | 34.28 |
| 2007 | 35.51 |
| 2008 | 37.93 |
| 2009 | |
| 2010 | 42.55 |
| 2011 | 44.19 |
| 2012 | 44.44 |
| 2013 | 44.88 |
| 2014 | 45 |
| 2015 | 45.81 |
| 2016 | 47.95 |
| 2017 | 48.63 |
| 2018 | 47.7 |