| 年度 | 实际值 |
|---|---|
| 1995 | 26.8 |
| 1996 | 26.5 |
| 1997 | 26.36 |
| 1998 | 28.2 |
| 1999 | 28.5 |
| 2000 | 29.7 |
| 2001 | 30.47 |
| 2002 | 32.48 |
| 2003 | 33.26 |
| 2004 | 34.05 |
| 2005 | 42.93 |
| 2006 | 43.43 |
| 2007 | 44.57 |
| 2008 | 45.72 |
| 2009 | |
| 2010 | 47.32 |
| 2011 | 48.19 |
| 2012 | 48.97 |
| 2013 | 49.74 |
| 2014 | 50.58 |
| 2015 | 52.9 |
| 2016 | 53.64 |
| 2017 | 52.53 |
| 2018 | 52.27 |