| 年度 | 实际值 |
|---|---|
| 1995 | 46.5 |
| 1996 | 43.7 |
| 1997 | 25.77 |
| 1998 | 53.6 |
| 1999 | 51.2 |
| 2000 | 51.1 |
| 2001 | 47.92 |
| 2002 | 47.12 |
| 2003 | 47.53 |
| 2004 | 47.41 |
| 2005 | 47.24 |
| 2006 | 46.78 |
| 2007 | 45.11 |
| 2008 | 45.33 |
| 2009 | |
| 2010 | 47.51 |
| 2011 | 49.02 |
| 2012 | 49.08 |
| 2013 | 47.64 |
| 2014 | 43.55 |
| 2015 | 41.94 |
| 2016 | 39.47 |
| 2017 | 40.14 |
| 2018 | 38.86 |