Year	Percent
1960-01-01	6.4179800000000000
1961-01-01	6.4013800000000005
1962-01-01	6.3636400000000000
1963-01-01	5.2759300000000010
1964-01-01	4.4243800000000000
1965-01-01	4.4982600000000000
1966-01-01	4.2383400000000000
1967-01-01	4.1263100000000000
1968-01-01	4.2264900000000000
1969-01-01	4.7928400000000000
1970-01-01	5.5948900000000000
1971-01-01	5.9096699999999990
1972-01-01	6.3876800000000005
1973-01-01	6.2219900000000000
1974-01-01	5.8533800000000005
1975-01-01	5.9639500000000000
1976-01-01	5.7626200000000000
1977-01-01	5.8986700000000000
1978-01-01	6.0543800000000000
1979-01-01	6.5817500000000000
1980-01-01	7.8578500000000000
1981-01-01	8.3485500000000000
1982-01-01	8.6238000000000000
1983-01-01	8.4663100000000000
1984-01-01	8.2444399999999990
1985-01-01	8.3082400000000000
1986-01-01	7.9618899999999995
1987-01-01	7.5343800000000005
1988-01-01	7.0720000000000000
1989-01-01	7.0095100000000010
1990-01-01	7.0786200000000000
1991-01-01	7.1905399999999995
1992-01-01	7.3596600000000010
1993-01-01	7.3112200000000000
1994-01-01	7.0133000000000000
1995-01-01	6.7374800000000010
1996-01-01	6.9343600000000010
1997-01-01	7.8320399999999990
1998-01-01	10.0299000000000000
1999-01-01	9.5891300000000000
2000-01-01	8.9584500000000000
2001-01-01	8.4041199999999990
2002-01-01	7.1189800000000005
2003-01-01	6.6897199999999994
2004-01-01	6.8127000000000000
2005-01-01	7.2025800000000000