| 年度 | 实际值 |
|---|---|
| 1995 | 51.8 |
| 1996 | 48.2 |
| 1997 | 41.93 |
| 1998 | 50.2 |
| 1999 | 53.9 |
| 2000 | 50.5 |
| 2001 | 51.31 |
| 2002 | 52.24 |
| 2003 | 54.79 |
| 2004 | 58.45 |
| 2005 | 58.05 |
| 2006 | 61.22 |
| 2007 | 62.46 |
| 2008 | 65.48 |
| 2009 | |
| 2010 | 63.13 |
| 2011 | 67.34 |
| 2012 | 67.65 |
| 2013 | 67.1 |
| 2014 | 64.75 |
| 2015 | 64.08 |
| 2016 | 60.12 |
| 2017 | 51.52 |
| 2018 | 50.04 |