Year	Percent
1960-01-01	15.67590
1961-01-01	14.86300
1962-01-01	13.88760
1963-01-01	18.21950
1964-01-01	22.83390
1965-01-01	24.64090
1966-01-01	24.22000
1967-01-01	23.19420
1968-01-01	23.88870
1969-01-01	26.18330
1970-01-01	26.36170
1971-01-01	27.59430
1972-01-01	30.17440
1973-01-01	32.41940
1974-01-01	28.13650
1975-01-01	35.03240
1976-01-01	41.20930
1977-01-01	46.48870
1978-01-01	53.42230
1979-01-01	51.85020
1980-01-01	50.84670
1981-01-01	53.71350
1982-01-01	59.99290
1983-01-01	65.53900
1984-01-01	50.20670
1985-01-01	49.56640
1986-01-01	51.61020
1987-01-01	45.66840
1988-01-01	43.65150
1989-01-01	30.06840
1990-01-01	23.04070
1991-01-01	23.07370
1992-01-01	23.41910
1993-01-01	21.37280
1994-01-01	13.52050
1995-01-01	10.00920
1996-01-01	7.48875
1997-01-01	10.70400
1998-01-01	13.21050
1999-01-01	12.73130
2000-01-01	11.30740
2001-01-01	11.67550
2002-01-01	10.01410
2003-01-01	8.39410
2004-01-01	8.25813
2005-01-01	10.40440
2006-01-01	13.54250
2007-01-01	23.39690
2008-01-01	19.40610
2009-01-01	22.15850
2010-01-01	17.98600
2011-01-01	17.19870
2012-01-01	20.56500
2013-01-01	23.77620
2014-01-01	30.06790
2015-01-01	30.35260