| 年度 | 实际值 |
|---|---|
| 1995 | 32.8 |
| 1996 | 32.3 |
| 1997 | 32.2 |
| 1998 | 35.2 |
| 1999 | 35.5 |
| 2000 | 37.2 |
| 2001 | 40.21 |
| 2002 | 40.09 |
| 2003 | 40.69 |
| 2004 | 39.65 |
| 2005 | 45.9 |
| 2006 | 44.15 |
| 2007 | 43.42 |
| 2008 | 43.83 |
| 2009 | |
| 2010 | 44.19 |
| 2011 | 43.38 |
| 2012 | 44.14 |
| 2013 | 45.01 |
| 2014 | 45.63 |
| 2015 | 48.65 |
| 2016 | 51.55 |
| 2017 | 53.08 |
| 2018 | 53.94 |