| 年度 | 实际值 |
|---|---|
| 1992 | 29.43 |
| 1993 | 30.29 |
| 1994 | 31.06 |
| 1995 | 31.69 |
| 1996 | 32.3 |
| 1997 | 32.78 |
| 1998 | 32.84 |
| 1999 | 33.02 |
| 2000 | 34.3 |
| 2001 | 33.61 |
| 2002 | 34.01 |
| 2003 | 47.24 |
| 2004 | 48.04 |
| 2005 | 48.63 |
| 2006 | 48.93 |
| 2007 | 49.23 |
| 2008 | 49.72 |
| 2009 | |
| 2010 | 50.06 |
| 2011 | 51.4 |
| 2012 | 51.6 |
| 2013 | 52.1 |
| 2014 | 77.9 |
| 2015 | 78.6 |
| 2016 | 79 |
| 2017 | 79 |
| 2018 | 80 |