| 年度 | 实际值 |
|---|---|
| 1992 | 2.3 |
| 1993 | |
| 1994 | |
| 1995 | 2.5 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.0025 |
| 2000 | 3.0295 |
| 2001 | 3.0007 |
| 2002 | 2.9962 |
| 2003 | 2.9977 |
| 2004 | 2.9974 |
| 2005 | 2.9769 |
| 2006 | 2.952 |
| 2007 | 2.9425 |
| 2008 | 3.0175 |
| 2009 | 3.2456 |
| 2010 | 3.2432 |
| 2011 | 3.2429 |
| 2012 | 3.2348 |
| 2013 | 3.4127 |
| 2014 | 4.005 |
| 2015 | 4.2801 |