| 年度 | 实际值 |
|---|---|
| 1995 | 35 |
| 1996 | 37.8 |
| 1997 | 52.08 |
| 1998 | 32.9 |
| 1999 | 31.9 |
| 2000 | 35.1 |
| 2001 | 34.87 |
| 2002 | 37.87 |
| 2003 | 44.5 |
| 2004 | 49.68 |
| 2005 | 55.4 |
| 2006 | 58.24 |
| 2007 | 58.35 |
| 2008 | 58.41 |
| 2009 | |
| 2010 | 59.41 |
| 2011 | 58.25 |
| 2012 | 59.12 |
| 2013 | 58.88 |
| 2014 | 60.56 |
| 2015 | 58.49 |
| 2016 | 59.6 |
| 2017 | 59.35 |
| 2018 | 44.93 |