| 年度 | 实际值 |
|---|---|
| 1995 | 20.7 |
| 1996 | 22.1 |
| 1997 | 56.73 |
| 1998 | 14.3 |
| 1999 | 17.3 |
| 2000 | 23.5 |
| 2001 | 24.28 |
| 2002 | 24.85 |
| 2003 | 23.29 |
| 2004 | 25.02 |
| 2005 | 20.89 |
| 2006 | 21.26 |
| 2007 | 23.64 |
| 2008 | 22.84 |
| 2009 | |
| 2010 | 22.3 |
| 2011 | 24.48 |
| 2012 | 23.92 |
| 2013 | 24.83 |
| 2014 | 45.01 |
| 2015 | 49.35 |
| 2016 | 48.28 |
| 2017 | 50.45 |
| 2018 | 54.23 |