| 年度 | 实际值 |
|---|---|
| 1995 | 59.9 |
| 1996 | 60.2 |
| 1997 | 60.75 |
| 1998 | 61.1 |
| 1999 | 61.4 |
| 2000 | 60.6 |
| 2001 | 58.11 |
| 2002 | 58.12 |
| 2003 | 59.2 |
| 2004 | 59.88 |
| 2005 | 60.31 |
| 2006 | 60.55 |
| 2007 | 60.72 |
| 2008 | 59.79 |
| 2009 | |
| 2010 | 56.05 |
| 2011 | 55.05 |
| 2012 | 53.71 |
| 2013 | 53.01 |
| 2014 | 51.89 |
| 2015 | 50.45 |
| 2016 | 50.08 |
| 2017 | |
| 2018 | 48.22 |