| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 60 | 141 |
| 2015 | 59.9 | 140 |
| 2014 | 59.6 | 140 |
| 2013 | 59.3 | 140 |
| 2012 | 59 | 141 |
| 2011 | 58.7 | 141 |
| 2010 | 58.3 | 141 |
| 2009 | 57.9 | 143 |
| 2008 | 57.5 | 144 |
| 2007 | 57.1 | 144 |
| 2006 | 56.6 | 144 |
| 2005 | 56 | 144 |
| 2004 | 55.6 | 145 |
| 2003 | 55.2 | 147 |
| 2002 | 54.8 | 147 |
| 2001 | 54.5 | 147 |
| 2000 | 54.2 | 146 |
| 1999 | 54 | 145 |
| 1998 | 53.8 | 143 |
| 1997 | 53.7 | 144 |
| 1996 | 53.6 | 141 |
| 1995 | 53.5 | 138 |
| 1994 | 53.1 | 141 |
| 1993 | 52.8 | 141 |
| 1992 | 52.4 | 144 |
| 1991 | 52.1 | 152 |
| 1990 | 51.7 | 156 |
| 1989 | 51.6 | 154 |
| 1988 | 51.5 | 154 |
| 1987 | 51.4 | 152 |
| 1986 | 51.3 | 151 |