| 年度 | 实际值 |
|---|---|
| 1995 | 45.6 |
| 1996 | 35.6 |
| 1997 | 33.47 |
| 1998 | 33.1 |
| 1999 | 38.2 |
| 2000 | 39.5 |
| 2001 | 45.03 |
| 2002 | 43.39 |
| 2003 | 36.4 |
| 2004 | 44.75 |
| 2005 | 40.02 |
| 2006 | 38.18 |
| 2007 | 36.55 |
| 2008 | 36.15 |
| 2009 | |
| 2010 | 36.58 |
| 2011 | 32.29 |
| 2012 | 32.72 |
| 2013 | 32.63 |
| 2014 | 33.46 |
| 2015 | 34.55 |
| 2016 | 36.23 |
| 2017 | 47.05 |
| 2018 | 48.12 |