| 年度 | 实际值 |
|---|---|
| 1995 | 29.3 |
| 1996 | 30.4 |
| 1997 | 89.46 |
| 1998 | 33.3 |
| 1999 | 39.7 |
| 2000 | 37.9 |
| 2001 | 39.8 |
| 2002 | 39.13 |
| 2003 | 36.73 |
| 2004 | 33.45 |
| 2005 | 38.82 |
| 2006 | 39.22 |
| 2007 | 39.29 |
| 2008 | 31.19 |
| 2009 | |
| 2010 | 27.79 |
| 2011 | 27.51 |
| 2012 | 31.74 |
| 2013 | 40.76 |
| 2014 | 46.46 |
| 2015 | 47.81 |
| 2016 | 49.28 |
| 2017 | 49.66 |
| 2018 | 47.9 |