| 年度 | 实际值 |
|---|---|
| 1995 | 39.5 |
| 1996 | 40.9 |
| 1997 | 32.7 |
| 1998 | 41.6 |
| 1999 | 45.4 |
| 2000 | 45.8 |
| 2001 | 49.5 |
| 2002 | 50.09 |
| 2003 | 45.03 |
| 2004 | 40.27 |
| 2005 | 46.17 |
| 2006 | 49.58 |
| 2007 | 49.08 |
| 2008 | 52.54 |
| 2009 | |
| 2010 | 54.94 |
| 2011 | 42.43 |
| 2012 | 45.53 |
| 2013 | 49.23 |
| 2014 | 49.66 |
| 2015 | 52.22 |
| 2016 | 53.99 |
| 2017 | 53.59 |
| 2018 | 51.19 |