| 年度 | 实际值 |
|---|---|
| 1995 | 46.3 |
| 1996 | 49.3 |
| 1997 | 49.35 |
| 1998 | 51.9 |
| 1999 | 45.5 |
| 2000 | 41.6 |
| 2001 | 39.75 |
| 2002 | 38.14 |
| 2003 | 43.7 |
| 2004 | 49.71 |
| 2005 | 45.16 |
| 2006 | 54.93 |
| 2007 | 67.49 |
| 2008 | 69.13 |
| 2009 | |
| 2010 | 66.05 |
| 2011 | 56.03 |
| 2012 | 49.65 |
| 2013 | 45.27 |
| 2014 | 46.13 |
| 2015 | 44.12 |
| 2016 | 43.16 |
| 2017 | 36.79 |
| 2018 | 38.63 |