| 年度 | 实际值 |
|---|---|
| 1995 | 26.2 |
| 1996 | 27.1 |
| 1997 | 27.66 |
| 1998 | 27.8 |
| 1999 | 28.1 |
| 2000 | 29.4 |
| 2001 | 32.11 |
| 2002 | 33.26 |
| 2003 | 33.23 |
| 2004 | 33.1 |
| 2005 | 33.26 |
| 2006 | 33.65 |
| 2007 | 33.95 |
| 2008 | 34.96 |
| 2009 | |
| 2010 | 38.6 |
| 2011 | 39.78 |
| 2012 | 41.24 |
| 2013 | 42.12 |
| 2014 | 43.56 |
| 2015 | 45.1 |
| 2016 | 45.59 |
| 2017 | |
| 2018 | 48.16 |