| 年度 | 实际值 |
|---|---|
| 1995 | 37.9 |
| 1996 | 40.3 |
| 1997 | 32.79 |
| 1998 | 47.3 |
| 1999 | 49.3 |
| 2000 | 52.2 |
| 2001 | 52.31 |
| 2002 | 54.22 |
| 2003 | 55.8 |
| 2004 | 55.61 |
| 2005 | 49.39 |
| 2006 | 49.75 |
| 2007 | 50.67 |
| 2008 | 49.61 |
| 2009 | |
| 2010 | 50.92 |
| 2011 | 52.29 |
| 2012 | 53.67 |
| 2013 | 54.98 |
| 2014 | 46.29 |
| 2015 | 51.59 |
| 2016 | 53.03 |
| 2017 | 55.18 |
| 2018 | 57.56 |