| 年度 | 实际值 |
|---|---|
| 1995 | 32.2 |
| 1996 | 31.5 |
| 1997 | 31.85 |
| 1998 | 31.2 |
| 1999 | 31.8 |
| 2000 | 35.6 |
| 2001 | 36.48 |
| 2002 | 38.81 |
| 2003 | 41.08 |
| 2004 | 38.98 |
| 2005 | 36.56 |
| 2006 | 35.99 |
| 2007 | 36.51 |
| 2008 | 35.19 |
| 2009 | |
| 2010 | 35.92 |
| 2011 | 34.63 |
| 2012 | 35.01 |
| 2013 | 36.49 |
| 2014 | 38.28 |
| 2015 | 40.16 |
| 2016 | 43.38 |
| 2017 | |
| 2018 | 55.33 |