| 年度 | 实际值 |
|---|---|
| 1995 | 59 |
| 1996 | 61.6 |
| 1997 | 65.7 |
| 1998 | 65.5 |
| 1999 | 62.7 |
| 2000 | 65.2 |
| 2001 | 65.14 |
| 2002 | 64.72 |
| 2003 | 67.62 |
| 2004 | 69.92 |
| 2005 | 46.36 |
| 2006 | 43.66 |
| 2007 | 50.13 |
| 2008 | 51.33 |
| 2009 | |
| 2010 | 49.41 |
| 2011 | 49.96 |
| 2012 | 51.22 |
| 2013 | 50.72 |
| 2014 | 47.8 |
| 2015 | 43.27 |
| 2016 | 40.7 |
| 2017 | 37.9 |
| 2018 | 37.58 |