1989 1.8

2004 2.1

2000 2.5

1996 2.6

1999 2.6

2002 2.6

1999 2.7

1996 2.7

2003 2.7

1982 2.8

1990 2.9

1984 3.0

1998 3.1

1987 3.1

1996 3.2

1996 3.2

1994 3.2

2002 3.2

1986 3.3

2004 3.3