| 年度 | 实际值 |
|---|---|
| 1995 | 52.9 |
| 1996 | 52.2 |
| 1997 | 37.93 |
| 1998 | 51 |
| 1999 | 49.4 |
| 2000 | 49.4 |
| 2001 | 51.2 |
| 2002 | 52.31 |
| 2003 | 54.09 |
| 2004 | 57.78 |
| 2005 | 53.85 |
| 2006 | 56.13 |
| 2007 | 57.84 |
| 2008 | 57.98 |
| 2009 | |
| 2010 | 57.52 |
| 2011 | 58.71 |
| 2012 | 57.66 |
| 2013 | 59.11 |
| 2014 | 58.22 |
| 2015 | 55.26 |
| 2016 | 54.26 |
| 2017 | 53.35 |
| 2018 | 53.33 |