| 年度 | 实际值 |
|---|---|
| 1992 | 6.2 |
| 1993 | |
| 1994 | |
| 1995 | 5.3 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.8923 |
| 2000 | 3.7353 |
| 2001 | 5.0157 |
| 2002 | 5.1392 |
| 2003 | 5.1742 |
| 2004 | 5.4038 |
| 2005 | 5.2114 |
| 2006 | 5.1714 |
| 2007 | 5.217 |
| 2008 | 5.217 |
| 2009 | 5.2699 |
| 2010 | 5.2711 |
| 2011 | 5.3062 |
| 2012 | 5.2947 |
| 2013 | 5.2703 |
| 2014 | 5.3562 |
| 2015 | 2.8359 |