| 年度 | 实际值 |
|---|---|
| 1995 | 51.7 |
| 1996 | 51 |
| 1997 | 50.22 |
| 1998 | 47.9 |
| 1999 | 47.3 |
| 2000 | 48.6 |
| 2001 | 49.41 |
| 2002 | 50.54 |
| 2003 | 51.93 |
| 2004 | 53.66 |
| 2005 | 59.32 |
| 2006 | 60.53 |
| 2007 | 62.97 |
| 2008 | 65.81 |
| 2009 | |
| 2010 | 70.37 |
| 2011 | 70.74 |
| 2012 | 70.47 |
| 2013 | 71.73 |
| 2014 | 67.37 |
| 2015 | 65.28 |
| 2016 | 65.21 |
| 2017 | |
| 2018 | 63.31 |