Year	Percent
1980-01-01	9.5
1981-01-01	7.5
1982-01-01	7.0
1983-01-01	7.5
1984-01-01	7.5
1985-01-01	7.5
1986-01-01	4.0
1987-01-01	8.0
1988-01-01	8.0