| 年度 | 实际值 |
|---|---|
| 1992 | 10.8 |
| 1993 | |
| 1994 | |
| 1995 | 10.7 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 11.3355 |
| 2000 | 12.2578 |
| 2001 | 12.4915 |
| 2002 | 13.7028 |
| 2003 | 17.5236 |
| 2004 | 18.0292 |
| 2005 | 20.0403 |
| 2006 | 20.5379 |
| 2007 | 20.6484 |
| 2008 | 21.5368 |
| 2009 | 22.7615 |
| 2010 | 23.2977 |
| 2011 | 25.1083 |
| 2012 | 25.1692 |
| 2013 | 25.1858 |
| 2014 | 25.1787 |
| 2015 | 25.2106 |