| 年度 | 实际值 |
|---|---|
| 1995 | 52.4 |
| 1996 | 51.3 |
| 1997 | 34.96 |
| 1998 | 52.2 |
| 1999 | 53.3 |
| 2000 | 54.9 |
| 2001 | 53.83 |
| 2002 | 54.02 |
| 2003 | 41.98 |
| 2004 | 39.72 |
| 2005 | 42.22 |
| 2006 | 41.44 |
| 2007 | 41.62 |
| 2008 | 40.33 |
| 2009 | |
| 2010 | 39.59 |
| 2011 | 43.42 |
| 2012 | 42.54 |
| 2013 | 42.32 |
| 2014 | 42.04 |
| 2015 | 43.36 |
| 2016 | 44.35 |
| 2017 | 45.16 |
| 2018 | 44.87 |