| 年度 | 实际值 |
|---|---|
| 1992 | 7.1 |
| 1993 | |
| 1994 | |
| 1995 | 6.9 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 8.2975 |
| 2000 | 8.1456 |
| 2001 | 7.8216 |
| 2002 | 8.3676 |
| 2003 | 10.234 |
| 2004 | 10.7003 |
| 2005 | 10.7761 |
| 2006 | 10.7042 |
| 2007 | 10.7574 |
| 2008 | 10.9418 |
| 2009 | 10.5388 |
| 2010 | 11.5852 |
| 2011 | 11.9637 |
| 2012 | 11.7939 |
| 2013 | 11.7721 |
| 2014 | 11.7026 |
| 2015 | 12.3977 |