| 年度 | 实际值 |
|---|---|
| 1995 | 28.7 |
| 1996 | 23.5 |
| 1997 | 20.76 |
| 1998 | 19.8 |
| 1999 | 20.8 |
| 2000 | 20.9 |
| 2001 | 30 |
| 2002 | 32.94 |
| 2003 | 32.78 |
| 2004 | 31.45 |
| 2005 | 30.75 |
| 2006 | 30.66 |
| 2007 | 34.21 |
| 2008 | 34.54 |
| 2009 | |
| 2010 | 36.48 |
| 2011 | 35.51 |
| 2012 | 39.58 |
| 2013 | 44.25 |
| 2014 | 53.78 |
| 2015 | 58.54 |
| 2016 | 58.45 |
| 2017 | 63.18 |
| 2018 | 64.09 |