| 年度 | 实际值 |
|---|---|
| 1995 | 29.3 |
| 1996 | 27.2 |
| 1997 | 27.17 |
| 1998 | 28 |
| 1999 | 28.8 |
| 2000 | 29.7 |
| 2001 | 33.01 |
| 2002 | 33.73 |
| 2003 | 35.37 |
| 2004 | 34.23 |
| 2005 | 35.39 |
| 2006 | 34.2 |
| 2007 | 34.94 |
| 2008 | 34.66 |
| 2009 | |
| 2010 | 37.07 |
| 2011 | 38.56 |
| 2012 | 39.37 |
| 2013 | 40.17 |
| 2014 | 42.77 |
| 2015 | 44.87 |
| 2016 | 46.29 |
| 2017 | |
| 2018 | 48.46 |