| 年度 | 实际值 |
|---|---|
| 1995 | 57.3 |
| 1996 | 49.9 |
| 1997 | 49.94 |
| 1998 | 47.1 |
| 1999 | 51.4 |
| 2000 | 48.7 |
| 2001 | 48.06 |
| 2002 | 48.17 |
| 2003 | 49.86 |
| 2004 | 49.76 |
| 2005 | 42.97 |
| 2006 | 43.11 |
| 2007 | 43.85 |
| 2008 | 55.8 |
| 2009 | |
| 2010 | 60.38 |
| 2011 | 65.07 |
| 2012 | 66.23 |
| 2013 | 64.81 |
| 2014 | 60.74 |
| 2015 | 56.11 |
| 2016 | 56.63 |
| 2017 | 49.05 |
| 2018 | 48.59 |