| 年度 | 实际值 |
|---|---|
| 1995 | 64.8 |
| 1996 | 61 |
| 1997 | 56.63 |
| 1998 | 55.1 |
| 1999 | 54.2 |
| 2000 | 57.4 |
| 2001 | 59.75 |
| 2002 | 61.36 |
| 2003 | 62.44 |
| 2004 | 64.65 |
| 2005 | 61.7 |
| 2006 | 59.9 |
| 2007 | 59.08 |
| 2008 | 58.22 |
| 2009 | |
| 2010 | 57.01 |
| 2011 | 53.71 |
| 2012 | 52.48 |
| 2013 | 52.85 |
| 2014 | 48.8 |
| 2015 | 47.57 |
| 2016 | 45 |
| 2017 | 45.61 |
| 2018 | 45.66 |