| 年度 | 实际值 |
|---|---|
| 1995 | 35.2 |
| 1996 | 38 |
| 1997 | 32.58 |
| 1998 | 41.4 |
| 1999 | 40.9 |
| 2000 | 39 |
| 2001 | 39.35 |
| 2002 | 40.59 |
| 2003 | 36.88 |
| 2004 | 35.64 |
| 2005 | 40.16 |
| 2006 | 40.59 |
| 2007 | 40.95 |
| 2008 | 40.45 |
| 2009 | |
| 2010 | 33.27 |
| 2011 | 32.86 |
| 2012 | 33.79 |
| 2013 | 35.05 |
| 2014 | 37.58 |
| 2015 | 43.47 |
| 2016 | 40.85 |
| 2017 | 42.21 |
| 2018 | 47.75 |