| 年度 | 实际值 |
|---|---|
| 1995 | 39.5 |
| 1996 | 37.9 |
| 1997 | 39.4 |
| 1998 | 38.8 |
| 1999 | 39.5 |
| 2000 | 39.7 |
| 2001 | 40.48 |
| 2002 | 40.01 |
| 2003 | 41.75 |
| 2004 | 44.08 |
| 2005 | 38.27 |
| 2006 | 40.55 |
| 2007 | 43.3 |
| 2008 | 47.82 |
| 2009 | |
| 2010 | 49.25 |
| 2011 | 50.41 |
| 2012 | 50.95 |
| 2013 | 52.24 |
| 2014 | 52.49 |
| 2015 | 51.09 |
| 2016 | 50.1 |
| 2017 | |
| 2018 | 52.59 |