| 年度 | 实际值 |
|---|---|
| 1995 | 39.1 |
| 1996 | 40.4 |
| 1997 | 42.36 |
| 1998 | 44.8 |
| 1999 | 45.7 |
| 2000 | 44.9 |
| 2001 | 45.06 |
| 2002 | 47.79 |
| 2003 | 50.41 |
| 2004 | 52.74 |
| 2005 | 55.85 |
| 2006 | 56.2 |
| 2007 | 56.15 |
| 2008 | 55.46 |
| 2009 | |
| 2010 | 53.59 |
| 2011 | 52.2 |
| 2012 | 50.67 |
| 2013 | 49.01 |
| 2014 | 47.63 |
| 2015 | 46.28 |
| 2016 | 44.79 |
| 2017 | |
| 2018 | 44.23 |