| 年度 | 实际值 |
|---|---|
| 1995 | 33.2 |
| 1996 | 35 |
| 1997 | 33.97 |
| 1998 | 33.1 |
| 1999 | 39.8 |
| 2000 | 39 |
| 2001 | 41.51 |
| 2002 | 42.53 |
| 2003 | 43.1 |
| 2004 | 48.32 |
| 2005 | 47.73 |
| 2006 | 46.91 |
| 2007 | 44.1 |
| 2008 | 41.55 |
| 2009 | |
| 2010 | 38.01 |
| 2011 | 32.63 |
| 2012 | 32.28 |
| 2013 | 33.28 |
| 2014 | 34.79 |
| 2015 | 36.69 |
| 2016 | 37.62 |
| 2017 | 44.13 |
| 2018 | 46.25 |