| 年度 | 实际值 |
|---|---|
| 1995 | 40.9 |
| 1996 | 48 |
| 1997 | 48.08 |
| 1998 | 51.1 |
| 1999 | 45.6 |
| 2000 | 48.4 |
| 2001 | 49.03 |
| 2002 | 48.99 |
| 2003 | 47.71 |
| 2004 | 47.82 |
| 2005 | 51.91 |
| 2006 | 53.19 |
| 2007 | 54.08 |
| 2008 | 42.56 |
| 2009 | |
| 2010 | 38.28 |
| 2011 | 33.57 |
| 2012 | 32.53 |
| 2013 | 33.95 |
| 2014 | 37.61 |
| 2015 | 34.86 |
| 2016 | 35.07 |
| 2017 | 45.38 |
| 2018 | 45.58 |