Year	Percent
1960-01-01	19.782200000000000
1961-01-01	20.147700000000000
1962-01-01	20.905400000000000
1963-01-01	20.671100000000000
1964-01-01	18.741100000000000
1965-01-01	17.786500000000000
1966-01-01	17.499500000000000
1967-01-01	18.290400000000000
1968-01-01	19.526800000000000
1969-01-01	20.887900000000000
1970-01-01	14.750600000000000
1971-01-01	14.810700000000000
1972-01-01	13.388800000000000
1973-01-01	12.038100000000000
1974-01-01	14.664800000000000
1975-01-01	18.988800000000000
1976-01-01	18.742000000000000
1977-01-01	18.121300000000000
1978-01-01	17.490000000000000
1979-01-01	17.342700000000000
1980-01-01	18.000400000000000
1981-01-01	20.518800000000000
1982-01-01	21.613700000000000
1983-01-01	23.087700000000000
1984-01-01	23.483900000000000
1985-01-01	23.446500000000000
1986-01-01	23.446500000000000
1987-01-01	16.411800000000000
1988-01-01	15.329000000000000
1989-01-01	15.329000000000000
1990-01-01	19.631000000000000
1991-01-01	19.068200000000000
1992-01-01	19.011300000000000
1993-01-01	20.654900000000000
1994-01-01	22.581800000000000
1995-01-01	24.811200000000000
1996-01-01	27.084500000000000
1997-01-01	27.742300000000000
1998-01-01	28.589500000000000
1999-01-01	26.978100000000000
2000-01-01	22.270100000000000
2001-01-01	20.836800000000000
2002-01-01	20.891200000000000
2003-01-01	20.311000000000000
2004-01-01	21.484900000000000
2005-01-01	23.249100000000000
2006-01-01	25.745900000000000
2007-01-01	29.921600000000000
2008-01-01	32.169600000000000
2009-01-01	31.446700000000000
2010-01-01	30.107800000000000
2011-01-01	31.755400000000000
2012-01-01	35.407600000000000
2013-01-01	37.690700000000000
2014-01-01	40.150999999999996
2015-01-01	43.904800000000000
2016-01-01	46.108100000000000