| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 60.7 | 11 |
| 2015 | 62.9 | 14 |
| 2014 | 49.1 | 19 |
| 2013 | 45.4 | 19 |
| 2012 | 48 | 19 |
| 2011 | 76 | 18 |
| 2010 | 71.2 | 15 |
| 2009 | 72.4 | 18 |
| 2008 | 160.5 | 13 |
| 2007 | 98.8 | 17 |
| 2006 | 6.7 | 55 |
| 2005 | 6 | 55 |
| 2004 | 5.3 | 58 |
| 2003 | 61.7 | 17 |
| 2002 | 80.1 | 13 |
| 2001 | 111.2 | 9 |
| 2000 | 80 | 14 |
| 1999 | 68.6 | 8 |
| 1998 | 99.8 | 9 |
| 1997 | 93.9 | 6 |
| 1996 | 103.7 | 4 |
| 1995 | 80.2 | 5 |
| 1994 | 89.7 | 5 |
| 1993 | 69.1 | 4 |
| 1992 | 37.3 | 11 |
| 1991 | 38.8 | 7 |
| 1990 | 254.1 | 1 |
| 1989 | 242.1 | 1 |
| 1988 | 276.9 | 1 |
| 1987 | 329 | 1 |
| 1986 | 101.5 | 1 |