| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 32.4 | 17 |
| 2015 | 42.9 | 14 |
| 2014 | 32.7 | 22 |
| 2013 | 35 | 20 |
| 2012 | 35.3 | 20 |
| 2011 | 41.9 | 19 |
| 2010 | 43.7 | 21 |
| 2009 | 52.3 | 18 |
| 2008 | 111.7 | 8 |
| 2007 | 94.6 | 20 |
| 2006 | 65 | 17 |
| 2005 | 45 | 20 |
| 2004 | 41.9 | 23 |
| 2003 | 40.6 | 21 |
| 2002 | 41.9 | 17 |
| 2001 | 66.7 | 12 |
| 2000 | 93.7 | 10 |
| 1999 | 59.5 | 13 |
| 1998 | 65.5 | 7 |
| 1997 | 44.5 | 10 |
| 1996 | 6 | 36 |
| 1995 | 22.4 | 15 |
| 1994 | 27.4 | 12 |
| 1993 | 25.6 | 9 |
| 1992 | 20.3 | 9 |
| 1991 | 23.5 | 8 |
| 1990 | 30.7 | 7 |
| 1989 | 25 | 8 |
| 1988 | 24.7 | 7 |
| 1987 | 32.8 | 7 |
| 1986 | 14.6 | 8 |