| 年度 | 实际值 |
|---|---|
| 1995 | 51.7 |
| 1996 | 54.8 |
| 1997 | 51.16 |
| 1998 | 45.8 |
| 1999 | 47 |
| 2000 | 44.6 |
| 2001 | 43.5 |
| 2002 | 47.37 |
| 2003 | 46.07 |
| 2004 | 43.72 |
| 2005 | 42.92 |
| 2006 | 37.25 |
| 2007 | 31.1 |
| 2008 | 39.09 |
| 2009 | |
| 2010 | 41.79 |
| 2011 | 43.48 |
| 2012 | 45.4 |
| 2013 | 48.94 |
| 2014 | 50.49 |
| 2015 | 53.64 |
| 2016 | 48.64 |
| 2017 | 49.12 |
| 2018 | 50.43 |