| 年度 | 实际值 |
|---|---|
| 1995 | 35.3 |
| 1996 | 37.1 |
| 1997 | 43.11 |
| 1998 | 35.1 |
| 1999 | 36.5 |
| 2000 | 36.9 |
| 2001 | 40.18 |
| 2002 | 39.84 |
| 2003 | 42.39 |
| 2004 | 42.12 |
| 2005 | 40.91 |
| 2006 | 41.36 |
| 2007 | 36.48 |
| 2008 | 35.58 |
| 2009 | |
| 2010 | 36.9 |
| 2011 | 33.12 |
| 2012 | 34.57 |
| 2013 | 35.96 |
| 2014 | 36.94 |
| 2015 | 39.5 |
| 2016 | 45.39 |
| 2017 | 52.97 |
| 2018 | 53.85 |