| 年度 | 实际值 |
|---|---|
| 1995 | 50 |
| 1996 | 49.3 |
| 1997 | 61.06 |
| 1998 | 47.1 |
| 1999 | 46.3 |
| 2000 | 46.3 |
| 2001 | 48.79 |
| 2002 | 48.72 |
| 2003 | 50.51 |
| 2004 | 51.93 |
| 2005 | 49.46 |
| 2006 | 48.41 |
| 2007 | 47.71 |
| 2008 | 47.28 |
| 2009 | |
| 2010 | 44.52 |
| 2011 | 44.7 |
| 2012 | 43.03 |
| 2013 | 41.15 |
| 2014 | 40.14 |
| 2015 | 37.14 |
| 2016 | 34.64 |
| 2017 | 33.61 |
| 2018 | 33.13 |