| 年度 | 实际值 |
|---|---|
| 1995 | 38.5 |
| 1996 | 37 |
| 1997 | 40.64 |
| 1998 | 35.7 |
| 1999 | 36.7 |
| 2000 | 37.9 |
| 2001 | 37.39 |
| 2002 | 37.93 |
| 2003 | 37.12 |
| 2004 | 37.24 |
| 2005 | 35.86 |
| 2006 | 36.07 |
| 2007 | 36.61 |
| 2008 | 37.19 |
| 2009 | |
| 2010 | 36.04 |
| 2011 | 38.77 |
| 2012 | 40.62 |
| 2013 | 42 |
| 2014 | 43.89 |
| 2015 | 45.09 |
| 2016 | 46.26 |
| 2017 | 47.12 |
| 2018 | 48.52 |