| 年度 | 实际值 |
|---|---|
| 1995 | 30.3 |
| 1996 | 28.8 |
| 1997 | 28.58 |
| 1998 | 30.2 |
| 1999 | 31.1 |
| 2000 | 31.6 |
| 2001 | 32.79 |
| 2002 | 39.09 |
| 2003 | 38.45 |
| 2004 | 37.95 |
| 2005 | 43.32 |
| 2006 | 42.32 |
| 2007 | 44.99 |
| 2008 | 40 |
| 2009 | |
| 2010 | 43.19 |
| 2011 | 41.93 |
| 2012 | 42.07 |
| 2013 | 45.52 |
| 2014 | 47.94 |
| 2015 | 48.91 |
| 2016 | 50.43 |
| 2017 | |
| 2018 | 55.82 |