| 年度 | 实际值 |
|---|---|
| 1992 | 41 |
| 1993 | |
| 1994 | |
| 1995 | 40.1 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 39.8 |
| 2000 | 39.7988 |
| 2001 | 39.7518 |
| 2002 | 39.7829 |
| 2003 | 40.0356 |
| 2004 | 40.1546 |
| 2005 | 35.04 |
| 2006 | 35.1086773515827 |
| 2007 | 35.19 |
| 2008 | 35.34 |
| 2009 | 41.2042 |
| 2010 | 41.3428 |
| 2011 | 41.3321 |
| 2012 | 41.6386 |
| 2013 | 41.9264 |
| 2014 | 34.36 |
| 2015 | 34.4261 |
| 2016 | 41 |
| 2017 | 42 |