| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 59.8 | 12 |
| 2015 | 63.2 | 13 |
| 2014 | 54.6 | 18 |
| 2013 | 57.7 | 14 |
| 2012 | 65.3 | 12 |
| 2011 | 94.2 | 10 |
| 2010 | 77.8 | 13 |
| 2009 | 66.7 | 21 |
| 2008 | 122.8 | 19 |
| 2007 | 105.8 | 12 |
| 2006 | 78.4 | 14 |
| 2005 | 76.2 | 14 |
| 2004 | 70.2 | 15 |
| 2003 | 72 | 14 |
| 2002 | 76.5 | 14 |
| 2001 | 64.1 | 20 |
| 2000 | 57.2 | 24 |
| 1999 | 46.5 | 20 |
| 1998 | 47.3 | 24 |
| 1997 | 50.8 | 22 |
| 1996 | 46.4 | 14 |
| 1995 | 40 | 18 |
| 1994 | 45.5 | 15 |
| 1993 | 32.6 | 17 |
| 1992 | 31.1 | 16 |
| 1991 | 31.5 | 14 |
| 1990 | 37.2 | 14 |
| 1989 | 31 | 17 |
| 1988 | 29.8 | 12 |
| 1987 | 37.3 | 14 |
| 1986 | 19 | 13 |