| 年度 | 实际值 |
|---|---|
| 1995 | 51.9 |
| 1996 | 53 |
| 1997 | 50.05 |
| 1998 | 57 |
| 1999 | 57.2 |
| 2000 | 56.6 |
| 2001 | 57.59 |
| 2002 | 57.54 |
| 2003 | 58.08 |
| 2004 | 58.05 |
| 2005 | 59.84 |
| 2006 | 60.02 |
| 2007 | 60.05 |
| 2008 | 59.43 |
| 2009 | |
| 2010 | 60.87 |
| 2011 | 58.19 |
| 2012 | 56.55 |
| 2013 | 55.05 |
| 2014 | 53.15 |
| 2015 | 52.07 |
| 2016 | 50.83 |
| 2017 | 50.17 |
| 2018 | 48.84 |