| 年度 | 实际值 |
|---|---|
| 1995 | 30.7 |
| 1996 | 33.3 |
| 1997 | 29.7 |
| 1998 | 30.1 |
| 1999 | 30.9 |
| 2000 | 31.1 |
| 2001 | 34.22 |
| 2002 | 40.39 |
| 2003 | 39.33 |
| 2004 | 39.57 |
| 2005 | 46.01 |
| 2006 | 45.42 |
| 2007 | 50.1 |
| 2008 | 50.1 |
| 2009 | |
| 2010 | 46.83 |
| 2011 | 46.41 |
| 2012 | 46.87 |
| 2013 | 52.01 |
| 2014 | 53.83 |
| 2015 | 53.25 |
| 2016 | 54.56 |
| 2017 | 58.17 |
| 2018 | 58.22 |