| 年度 | 实际值 |
|---|---|
| 1995 | 50.2 |
| 1996 | 50.2 |
| 1997 | 39.44 |
| 1998 | 48.8 |
| 1999 | 48.4 |
| 2000 | 49.8 |
| 2001 | 52 |
| 2002 | 45.7 |
| 2003 | 47.09 |
| 2004 | 46.58 |
| 2005 | 42.72 |
| 2006 | 40.68 |
| 2007 | 36.32 |
| 2008 | 35.21 |
| 2009 | |
| 2010 | 33.54 |
| 2011 | 32.27 |
| 2012 | 33.5 |
| 2013 | 34.66 |
| 2014 | 38.65 |
| 2015 | 41.89 |
| 2016 | 43.77 |
| 2017 | 46.83 |
| 2018 | 46.93 |