| 年度 | 实际值 |
|---|---|
| 1995 | 32.2 |
| 1996 | 28.4 |
| 1997 | 31.74 |
| 1998 | 37.8 |
| 1999 | 40.5 |
| 2000 | 41 |
| 2001 | 40.32 |
| 2002 | 38.94 |
| 2003 | 37.98 |
| 2004 | 36.68 |
| 2005 | 43.46 |
| 2006 | 40.34 |
| 2007 | 40.24 |
| 2008 | 37.8 |
| 2009 | |
| 2010 | 43.95 |
| 2011 | 42.7 |
| 2012 | 44.1 |
| 2013 | 45.59 |
| 2014 | 49.59 |
| 2015 | 53.89 |
| 2016 | 57.04 |
| 2017 | 57.06 |
| 2018 | 56.04 |