| 年度 | 实际值 |
|---|---|
| 1995 | 56 |
| 1996 | 53.1 |
| 1997 | 64.91 |
| 1998 | 45.8 |
| 1999 | 43.9 |
| 2000 | 41.3 |
| 2001 | 41.78 |
| 2002 | 39.66 |
| 2003 | 39.21 |
| 2004 | 39.2 |
| 2005 | 42.91 |
| 2006 | 43.44 |
| 2007 | 43.23 |
| 2008 | 44.68 |
| 2009 | |
| 2010 | 43.35 |
| 2011 | 41.92 |
| 2012 | 40.61 |
| 2013 | 39.76 |
| 2014 | 40.99 |
| 2015 | 36.5 |
| 2016 | 35.94 |
| 2017 | 34.99 |
| 2018 | 33.98 |