| 年度 | 实际值 |
|---|---|
| 1995 | 32.6 |
| 1996 | 25.3 |
| 1997 | 27.54 |
| 1998 | 38.8 |
| 1999 | 39.3 |
| 2000 | 37.3 |
| 2001 | 41.42 |
| 2002 | 40.39 |
| 2003 | 39.72 |
| 2004 | 38.14 |
| 2005 | 34.78 |
| 2006 | 35.32 |
| 2007 | 39.69 |
| 2008 | 36.75 |
| 2009 | |
| 2010 | 39.27 |
| 2011 | 40.97 |
| 2012 | 42.65 |
| 2013 | 43.7 |
| 2014 | 43.47 |
| 2015 | 45.23 |
| 2016 | 45.76 |
| 2017 | 45.53 |
| 2018 | 45.91 |