| 年度 | 实际值 |
|---|---|
| 1995 | 50.1 |
| 1996 | 53.7 |
| 1997 | 55.94 |
| 1998 | 56.9 |
| 1999 | 57.1 |
| 2000 | 58 |
| 2001 | 57.72 |
| 2002 | 57.58 |
| 2003 | 58.87 |
| 2004 | 57.06 |
| 2005 | 57.06 |
| 2006 | 58.34 |
| 2007 | 58.94 |
| 2008 | 58.86 |
| 2009 | |
| 2010 | 58.94 |
| 2011 | 58.44 |
| 2012 | 58.17 |
| 2013 | 57.89 |
| 2014 | 56.56 |
| 2015 | 54.97 |
| 2016 | 53.85 |
| 2017 | |
| 2018 | 52.68 |