| 年度 | 实际值 |
|---|---|
| 1995 | 39.1 |
| 1996 | 53.8 |
| 1997 | 49.55 |
| 1998 | 58.5 |
| 1999 | 52.1 |
| 2000 | 51.1 |
| 2001 | 45.25 |
| 2002 | 47.92 |
| 2003 | 55.67 |
| 2004 | 46.29 |
| 2005 | 50.65 |
| 2006 | 53.49 |
| 2007 | 54.69 |
| 2008 | 55.17 |
| 2009 | |
| 2010 | 55.75 |
| 2011 | 61.12 |
| 2012 | 60.86 |
| 2013 | 61.11 |
| 2014 | 60.62 |
| 2015 | 59.64 |
| 2016 | 55.77 |
| 2017 | 45.75 |
| 2018 | 45.22 |