| 年度 | 实际值 |
|---|---|
| 1995 | 38.7 |
| 1996 | 43.9 |
| 1997 | 45.56 |
| 1998 | 48.6 |
| 1999 | 49.2 |
| 2000 | 47.3 |
| 2001 | 47.58 |
| 2002 | 48.46 |
| 2003 | 46.55 |
| 2004 | 43.93 |
| 2005 | 42.11 |
| 2006 | 40.86 |
| 2007 | 40.81 |
| 2008 | 38.15 |
| 2009 | |
| 2010 | 45.34 |
| 2011 | 46.59 |
| 2012 | 47.75 |
| 2013 | 48.76 |
| 2014 | 49.68 |
| 2015 | 52.15 |
| 2016 | 56.44 |
| 2017 | 58.15 |
| 2018 | 58.62 |