| 年度 | 实际值 |
|---|---|
| 1995 | 43.3 |
| 1996 | 42 |
| 1997 | 43.37 |
| 1998 | 40.1 |
| 1999 | 42.1 |
| 2000 | 40.5 |
| 2001 | 39.22 |
| 2002 | 37.94 |
| 2003 | 38.3 |
| 2004 | 39.17 |
| 2005 | 39.6 |
| 2006 | 38.89 |
| 2007 | 39.54 |
| 2008 | 39.97 |
| 2009 | |
| 2010 | 39.86 |
| 2011 | 31.49 |
| 2012 | 38.45 |
| 2013 | 38.66 |
| 2014 | 39.04 |
| 2015 | 40.61 |
| 2016 | 42.02 |
| 2017 | 54.06 |
| 2018 | 55.68 |