| 年度 | 实际值 |
|---|---|
| 1995 | 41.6 |
| 1996 | 39.7 |
| 1997 | 51.07 |
| 1998 | 28.3 |
| 1999 | 28.8 |
| 2000 | 31.7 |
| 2001 | 32.72 |
| 2002 | 33.95 |
| 2003 | 40.87 |
| 2004 | 41.57 |
| 2005 | 41.64 |
| 2006 | 40.58 |
| 2007 | 41.61 |
| 2008 | 42.64 |
| 2009 | |
| 2010 | 45.45 |
| 2011 | 49.92 |
| 2012 | 49.25 |
| 2013 | 46.74 |
| 2014 | 42.11 |
| 2015 | 41.96 |
| 2016 | 42.82 |
| 2017 | 43.97 |
| 2018 | 43.67 |