| 年度 | 实际值 |
|---|---|
| 1995 | 23.2 |
| 1996 | 26.3 |
| 1997 | 32.81 |
| 1998 | 28.4 |
| 1999 | 27.2 |
| 2000 | 31.2 |
| 2001 | 27.78 |
| 2002 | 28.98 |
| 2003 | 33.09 |
| 2004 | 37.78 |
| 2005 | 44.85 |
| 2006 | 49.14 |
| 2007 | 51.17 |
| 2008 | 53.69 |
| 2009 | |
| 2010 | 56.18 |
| 2011 | 58.28 |
| 2012 | 58.97 |
| 2013 | 59.15 |
| 2014 | 58.45 |
| 2015 | 57.43 |
| 2016 | 57.19 |
| 2017 | |
| 2018 | 48.68 |