| 年度 | 实际值 |
|---|---|
| 1995 | 42.5 |
| 1996 | 36.7 |
| 1997 | 36.45 |
| 1998 | 43.1 |
| 1999 | 39.3 |
| 2000 | 42.7 |
| 2001 | 42.28 |
| 2002 | 42.91 |
| 2003 | 41.57 |
| 2004 | 40.71 |
| 2005 | 35.13 |
| 2006 | 35.33 |
| 2007 | 35.75 |
| 2008 | 35.12 |
| 2009 | |
| 2010 | 35.31 |
| 2011 | 37.25 |
| 2012 | 38.04 |
| 2013 | 37.67 |
| 2014 | 43.74 |
| 2015 | 45.88 |
| 2016 | 47.96 |
| 2017 | 45.08 |
| 2018 | 46.81 |