Year	Percent
1980-01-01	4.37
1981-01-01	5.69
1982-01-01	5.78
1983-01-01	4.75
1984-01-01	4.91
1985-01-01	5.18
1986-01-01	4.77
1987-01-01	5.15
1988-01-01	4.55
1989-01-01	4.42
1990-01-01	4.44
1991-01-01	5.00
1992-01-01	6.01
1993-01-01	6.78
1994-01-01	6.84
1995-01-01	7.11
1996-01-01	6.60
1997-01-01	6.08
1998-01-01	6.04
1999-01-01	6.23
2000-01-01	6.22
2001-01-01	6.88
2002-01-01	7.32