| 年度 | 实际值 |
|---|---|
| 1995 | 55.8 |
| 1996 | 56.3 |
| 1997 | 57.24 |
| 1998 | 57.8 |
| 1999 | 57.2 |
| 2000 | 56.6 |
| 2001 | 55.62 |
| 2002 | 55.52 |
| 2003 | 55.71 |
| 2004 | 56.33 |
| 2005 | 53.14 |
| 2006 | 53.94 |
| 2007 | 54.21 |
| 2008 | 53.69 |
| 2009 | |
| 2010 | 51.47 |
| 2011 | 50.69 |
| 2012 | 49.61 |
| 2013 | 48.86 |
| 2014 | 47.02 |
| 2015 | 45.53 |
| 2016 | 44.6 |
| 2017 | |
| 2018 | 42.57 |