| 年度 | 实际值 |
|---|---|
| 1992 | 11.4 |
| 1993 | |
| 1994 | |
| 1995 | 10.6 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 11.68 |
| 2000 | 10.8505 |
| 2001 | 11.0856 |
| 2002 | 10.9507 |
| 2003 | 10.2408 |
| 2004 | 11.1837 |
| 2005 | 11.3911 |
| 2006 | 11.473 |
| 2007 | 12.408 |
| 2008 | 12.1923 |
| 2009 | 11.7099 |
| 2010 | 11.253 |
| 2011 | 9.6318 |
| 2012 | 9.3453 |
| 2013 | 8.7312 |
| 2014 | 8.1879 |
| 2015 | 8.0165 |