| 年度 | 实际值 |
|---|---|
| 1995 | 32.2 |
| 1996 | 31 |
| 1997 | 33.46 |
| 1998 | 31.6 |
| 1999 | 26.8 |
| 2000 | 27.3 |
| 2001 | 27.14 |
| 2002 | 26.52 |
| 2003 | 30.79 |
| 2004 | 33.6 |
| 2005 | 39.47 |
| 2006 | 43.4 |
| 2007 | 40.94 |
| 2008 | 44.88 |
| 2009 | |
| 2010 | 39.49 |
| 2011 | 46.65 |
| 2012 | 55.8 |
| 2013 | 58.25 |
| 2014 | 59.91 |
| 2015 | 58.01 |
| 2016 | 58.72 |
| 2017 | 62.12 |
| 2018 | 55.75 |