| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 80.9 | 7 |
| 2015 | 77.8 | 10 |
| 2014 | 72.2 | 12 |
| 2013 | 98.7 | 7 |
| 2012 | 61.3 | 14 |
| 2011 | 80.2 | 16 |
| 2010 | 80.1 | 12 |
| 2009 | 71.6 | 19 |
| 2008 | 102.8 | 24 |
| 2007 | 57.2 | 23 |
| 2006 | 69.2 | 18 |
| 2005 | 72.5 | 16 |
| 2004 | 101.3 | 9 |
| 2003 | 87.8 | 8 |
| 2002 | 90.7 | 11 |
| 2001 | 86.4 | 13 |
| 2000 | 66.2 | 20 |
| 1999 | 65.2 | 10 |
| 1998 | 66.2 | 16 |
| 1997 | 77.1 | 9 |
| 1996 | 6.9 | 44 |
| 1995 | 42 | 16 |
| 1994 | 63.8 | 10 |
| 1993 | 68 | 5 |
| 1992 | 124.7 | 2 |
| 1991 | 51 | 6 |
| 1990 | 76.9 | 4 |
| 1989 | 55.1 | 7 |