| 年度 | 实际值 |
|---|---|
| 1995 | 55.3 |
| 1996 | 52.7 |
| 1997 | 34.89 |
| 1998 | 51.9 |
| 1999 | 52.5 |
| 2000 | 53.7 |
| 2001 | 53.34 |
| 2002 | 50.8 |
| 2003 | 50.69 |
| 2004 | 50.22 |
| 2005 | 55.35 |
| 2006 | 52.99 |
| 2007 | 54.22 |
| 2008 | 51.58 |
| 2009 | |
| 2010 | 54.52 |
| 2011 | 53.81 |
| 2012 | 54.15 |
| 2013 | 53.33 |
| 2014 | 54.75 |
| 2015 | 54.68 |
| 2016 | 55.22 |
| 2017 | 54.56 |
| 2018 | 55.45 |