| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 40.9 | 16 |
| 2015 | 65 | 12 |
| 2014 | 44.9 | 24 |
| 2013 | 40.9 | 20 |
| 2012 | 38 | 22 |
| 2011 | 63.6 | 23 |
| 2010 | 54.9 | 24 |
| 2009 | 61.3 | 23 |
| 2008 | 118 | 20 |
| 2007 | 75.9 | 19 |
| 2006 | 44.1 | 24 |
| 2005 | 39.9 | 23 |
| 2004 | 46.9 | 24 |
| 2003 | 38.2 | 25 |
| 2002 | 38.6 | 24 |
| 2001 | 47.1 | 24 |
| 2000 | 59.8 | 23 |
| 1999 | 37.4 | 24 |
| 1998 | 59.9 | 19 |
| 1997 | 109.6 | 5 |
| 1996 | 37 | 21 |
| 1995 | 31.5 | 23 |
| 1994 | 46.7 | 14 |
| 1993 | 34.3 | 15 |
| 1992 | 45.6 | 8 |
| 1991 | 31.6 | 13 |
| 1990 | 41.5 | 12 |
| 1989 | 44.6 | 11 |
| 1988 | 31.5 | 10 |
| 1987 | 84 | 5 |
| 1986 | 28.4 | 9 |