| 年度 | 实际值 |
|---|---|
| 1995 | 31.3 |
| 1996 | 24.8 |
| 1997 | 41.06 |
| 1998 | 23.5 |
| 1999 | 29.9 |
| 2000 | 34.6 |
| 2001 | 37.92 |
| 2002 | 40.19 |
| 2003 | 38.27 |
| 2004 | 35.49 |
| 2005 | 45.07 |
| 2006 | 37.66 |
| 2007 | 27.6 |
| 2008 | 26.15 |
| 2009 | |
| 2010 | 29.14 |
| 2011 | 38.77 |
| 2012 | 44.42 |
| 2013 | 45.59 |
| 2014 | 45.27 |
| 2015 | 47.33 |
| 2016 | 48.15 |
| 2017 | 54.87 |
| 2018 | 53 |