| 年度 | 实际值 |
|---|---|
| 1995 | 32.4 |
| 1996 | 30.9 |
| 1997 | 33.85 |
| 1998 | 36.7 |
| 1999 | 37.5 |
| 2000 | 37.8 |
| 2001 | 45.33 |
| 2002 | 44.69 |
| 2003 | 43.82 |
| 2004 | 40.54 |
| 2005 | 39.86 |
| 2006 | 37.07 |
| 2007 | 34.78 |
| 2008 | 32.63 |
| 2009 | |
| 2010 | 30.39 |
| 2011 | 28.91 |
| 2012 | 28.18 |
| 2013 | 26.45 |
| 2014 | 30.08 |
| 2015 | 33.67 |
| 2016 | 40.42 |
| 2017 | |
| 2018 | 49.26 |