| 年度 | 实际值 |
|---|---|
| 1995 | 28.5 |
| 1996 | 28.9 |
| 1997 | 38.38 |
| 1998 | 30.6 |
| 1999 | 32.2 |
| 2000 | 31.8 |
| 2001 | 28.92 |
| 2002 | 37.03 |
| 2003 | 36.64 |
| 2004 | 37.12 |
| 2005 | 44.5 |
| 2006 | 46.04 |
| 2007 | 44.65 |
| 2008 | 44.31 |
| 2009 | |
| 2010 | 39.57 |
| 2011 | 37.54 |
| 2012 | 38.61 |
| 2013 | 39.3 |
| 2014 | 39.36 |
| 2015 | 40.9 |
| 2016 | 43.35 |
| 2017 | 47.1 |
| 2018 | 49.15 |