| 年度 | 实际值 |
|---|---|
| 1995 | 32.8 |
| 1996 | 36.9 |
| 1997 | 38.93 |
| 1998 | 38.8 |
| 1999 | 42.7 |
| 2000 | 44.7 |
| 2001 | 42.87 |
| 2002 | 43.33 |
| 2003 | 46.72 |
| 2004 | 49.63 |
| 2005 | 50.94 |
| 2006 | 52.46 |
| 2007 | 56.32 |
| 2008 | 60.17 |
| 2009 | |
| 2010 | 51.04 |
| 2011 | 54.83 |
| 2012 | 52.91 |
| 2013 | 51.08 |
| 2014 | 49.98 |
| 2015 | 46.84 |
| 2016 | 45.79 |
| 2017 | |
| 2018 | 36.27 |