| 年度 | 实际值 |
|---|---|
| 1992 | 29.4 |
| 1993 | 31.2 |
| 1994 | 32.45 |
| 1995 | 33.75 |
| 1996 | 35.12 |
| 1997 | 38.29 |
| 1998 | 39.1 |
| 1999 | 40.24 |
| 2000 | 39.72 |
| 2001 | 40.59 |
| 2002 | 41.2 |
| 2003 | 41.6 |
| 2004 | 42.23 |
| 2005 | 43.11 |
| 2006 | 43.35 |
| 2007 | 47.7 |
| 2008 | 48.27 |
| 2009 | |
| 2010 | 53 |
| 2011 | 54.1 |
| 2012 | 54.8 |
| 2013 | 55.3 |
| 2014 | |
| 2015 | 44.49 |
| 2016 | 44 |
| 2017 | 44 |
| 2018 | 44 |