| 年度 | 实际值 |
|---|---|
| 1995 | 32.7 |
| 1996 | 36.5 |
| 1997 | 37.54 |
| 1998 | 43.1 |
| 1999 | 44.1 |
| 2000 | 41.1 |
| 2001 | 37.96 |
| 2002 | 36.45 |
| 2003 | 35.85 |
| 2004 | 33.94 |
| 2005 | 37.08 |
| 2006 | 39.03 |
| 2007 | 40.02 |
| 2008 | 40.94 |
| 2009 | |
| 2010 | 39.38 |
| 2011 | 43.19 |
| 2012 | 44.45 |
| 2013 | 44.1 |
| 2014 | 48.5 |
| 2015 | 49.85 |
| 2016 | 52.57 |
| 2017 | 52.25 |
| 2018 | 52.34 |