| 年度 | 实际值 |
|---|---|
| 1992 | 58.4 |
| 1993 | |
| 1994 | |
| 1995 | 62 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 61 |
| 2000 | 61.73 |
| 2001 | 61.6 |
| 2002 | 61.77 |
| 2003 | 61.76 |
| 2004 | 61.49 |
| 2005 | 61.72 |
| 2006 | 61.77 |
| 2007 | 61.86 |
| 2008 | 61.89 |
| 2009 | 61.92 |
| 2010 | 61.85 |
| 2011 | 61.84 |
| 2012 | 61.74 |
| 2013 | 60.52 |
| 2014 | 60.64 |
| 2015 | 60.53 |
| 2016 | 60.1 |
| 2017 | 59.5 |
| 2018 | 59.1494 |