| 年度 | 实际值 |
|---|---|
| 1995 | 41.6 |
| 1996 | 38.2 |
| 1997 | 19.63 |
| 1998 | 44.8 |
| 1999 | 46 |
| 2000 | 47.8 |
| 2001 | 47.79 |
| 2002 | 47.53 |
| 2003 | 50.07 |
| 2004 | 45.4 |
| 2005 | 43.57 |
| 2006 | 41.75 |
| 2007 | 40.33 |
| 2008 | 40.56 |
| 2009 | |
| 2010 | 38.17 |
| 2011 | 32.48 |
| 2012 | 33.15 |
| 2013 | 35.59 |
| 2014 | 37.74 |
| 2015 | 39.64 |
| 2016 | 42.16 |
| 2017 | 44.1 |
| 2018 | 50.25 |