| 年度 | 实际值 |
|---|---|
| 1992 | 36.7 |
| 1993 | |
| 1994 | |
| 1995 | 37.4 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 37.8 |
| 2000 | 37.9 |
| 2001 | 37.96 |
| 2002 | 38.06 |
| 2003 | 38.07 |
| 2004 | 38.1 |
| 2005 | 38.2 |
| 2006 | 38.34 |
| 2007 | 38.52 |
| 2008 | 38.81 |
| 2009 | 38.95 |
| 2010 | 39.07 |
| 2011 | 39.2 |
| 2012 | 39.14 |
| 2013 | 39.44 |
| 2014 | 39.61 |
| 2015 | 39.82 |
| 2016 | 39.9202 |
| 2017 | 40 |