| 年度 | 实际值 |
|---|---|
| 1992 | 3.3 |
| 1993 | |
| 1994 | |
| 1995 | 3.2 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.3248 |
| 2000 | 3.3083 |
| 2001 | 3.1742 |
| 2002 | 3.1755 |
| 2003 | 3.0116 |
| 2004 | 3.0139 |
| 2005 | 2.9805 |
| 2006 | 2.2867 |
| 2007 | 2.3144 |
| 2008 | 2.2357 |
| 2009 | 2.1176 |
| 2010 | 2.4766 |
| 2011 | 2.5032 |
| 2012 | 3.4469 |
| 2013 | 2.6634 |
| 2014 | 3.1465 |
| 2015 | 3.1292 |