| 年度 | 实际值 |
|---|---|
| 1995 | 30.3 |
| 1996 | 30.8 |
| 1997 | 31.61 |
| 1998 | 28.3 |
| 1999 | 30.3 |
| 2000 | 29.1 |
| 2001 | 29.74 |
| 2002 | 31.55 |
| 2003 | 31.36 |
| 2004 | 30.99 |
| 2005 | 31.55 |
| 2006 | 35.07 |
| 2007 | 38.92 |
| 2008 | 38.4 |
| 2009 | |
| 2010 | 43.45 |
| 2011 | 42.06 |
| 2012 | 44.27 |
| 2013 | 45.59 |
| 2014 | 49.31 |
| 2015 | 53.27 |
| 2016 | 56.06 |
| 2017 | 59.51 |
| 2018 | 61.73 |