| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 47.7 | 12 |
| 2015 | 82 | 7 |
| 2014 | 72.1 | 12 |
| 2013 | 67.2 | 10 |
| 2012 | 64.7 | 9 |
| 2011 | 75.8 | 10 |
| 2010 | 96 | 9 |
| 2009 | 85.3 | 10 |
| 2008 | 105.6 | 9 |
| 2007 | 154 | 10 |
| 2006 | 118.5 | 9 |
| 2005 | 84.8 | 12 |
| 2004 | 80.5 | 12 |
| 2003 | 68.2 | 11 |
| 2002 | 64.3 | 11 |
| 2001 | 238.1 | 1 |
| 2000 | 266 | 2 |
| 1999 | 162 | 2 |
| 1998 | 61 | 9 |
| 1997 | 32.3 | 14 |
| 1996 | 16.2 | 22 |
| 1995 | 10.8 | 26 |
| 1994 | 13.1 | 24 |
| 1993 | 8.7 | 28 |
| 1992 | 6.1 | 23 |
| 1991 | 8.4 | 18 |
| 1990 | 8.5 | 19 |
| 1989 | 9.6 | 19 |
| 1988 | 7 | 15 |
| 1987 | 12.9 | 15 |
| 1986 | 6.3 | 18 |