Year	Percent
1961-01-01	11.259400000000000
1962-01-01	10.199300000000000
1963-01-01	8.050430000000000
1964-01-01	7.676400000000000
1965-01-01	8.124340000000000
1966-01-01	8.722180000000000
1967-01-01	8.413089999999999
1968-01-01	11.237300000000000
1969-01-01	10.667900000000000
1970-01-01	7.859960000000001
1971-01-01	8.676350000000000
1972-01-01	10.030100000000000
1973-01-01	11.237900000000000
1974-01-01	13.292400000000000
1975-01-01	13.470900000000000
1976-01-01	13.992400000000000
1977-01-01	16.469800000000000
1978-01-01	17.199800000000000
1979-01-01	16.866700000000000
1980-01-01	18.001300000000000
1981-01-01	19.600200000000000
1982-01-01	21.000999999999998
1983-01-01	22.363200000000000
1984-01-01	23.043000000000003
1985-01-01	25.299600000000000
1986-01-01	23.925200000000000
1987-01-01	25.130200000000000
1988-01-01	24.976700000000000
1989-01-01	26.340000000000000
1990-01-01	30.786900000000000
1991-01-01	36.390000000000000
1992-01-01	36.728000000000000
1993-01-01	37.608300000000000
1994-01-01	38.709900000000000
1995-01-01	39.647600000000000
1996-01-01	38.459000000000000
1997-01-01	36.671600000000000
1998-01-01	30.654100000000000
1999-01-01	25.578300000000000
2000-01-01	29.655400000000000
2001-01-01	29.739100000000000
2002-01-01	27.430800000000000
2003-01-01	28.271900000000000
2004-01-01	30.574400000000000
2005-01-01	34.315500000000000
2006-01-01	40.114500000000000
2007-01-01	44.603500000000000
2008-01-01	46.224000000000000
2009-01-01	47.686000000000010
2010-01-01	44.739400000000000
2011-01-01	50.640900000000000
2012-01-01	57.306500000000000
2013-01-01	56.874600000000000
2014-01-01	57.652600000000000
2015-01-01	61.515400000000000
2016-01-01	65.976500000000000