| 年度 | 实际值 |
|---|---|
| 1995 | 53.5 |
| 1996 | 54.9 |
| 1997 | 55.12 |
| 1998 | 53.8 |
| 1999 | 50.3 |
| 2000 | 49.2 |
| 2001 | 48.87 |
| 2002 | 48.88 |
| 2003 | 51.85 |
| 2004 | 53.56 |
| 2005 | 52.56 |
| 2006 | 53.19 |
| 2007 | 52.86 |
| 2008 | 55.24 |
| 2009 | |
| 2010 | 56.17 |
| 2011 | 57.72 |
| 2012 | 56.45 |
| 2013 | 55.96 |
| 2014 | 51.46 |
| 2015 | 49.29 |
| 2016 | 46.79 |
| 2017 | |
| 2018 | 43.88 |