| 年度 | 实际值 |
|---|---|
| 1995 | 38.5 |
| 1996 | 41.4 |
| 1997 | 39.18 |
| 1998 | 49.6 |
| 1999 | 51.1 |
| 2000 | 48 |
| 2001 | 51.35 |
| 2002 | 50.66 |
| 2003 | 47.04 |
| 2004 | 46.92 |
| 2005 | 45.19 |
| 2006 | 44.91 |
| 2007 | 45.91 |
| 2008 | 47.44 |
| 2009 | |
| 2010 | 50.82 |
| 2011 | 52.96 |
| 2012 | 55.15 |
| 2013 | 43.64 |
| 2014 | 45.24 |
| 2015 | 47 |
| 2016 | 47.76 |
| 2017 | 48.95 |
| 2018 | 49.7 |