Year	Percent
1967-01-01	0.90595800000000000
1968-01-01	0.83140100000000010
1969-01-01	0.86926700000000000
1970-01-01	0.64642600000000010
1971-01-01	0.31354499999999996
1972-01-01	0.37182700000000000
1973-01-01	0.67274300000000000
1974-01-01	1.36761000000000000
1975-01-01	2.97677999999999980
1976-01-01	6.04326000000000000
1977-01-01	9.19146999999999900
1978-01-01	6.37915000000000000
1979-01-01	2.53847000000000020
1980-01-01	1.76984000000000000
1981-01-01	2.01922000000000020
1982-01-01	4.90112000000000000
1983-01-01	13.06430000000000000
1984-01-01	24.89550000000000000
1985-01-01	37.54590000000000000
1986-01-01	51.22410000000000000
1987-01-01	69.88460000000000000
1988-01-01	69.70130000000000000
1989-01-01	73.53170000000000000
1990-01-01	56.33980000000000000
1991-01-01	49.44750000000000000
1992-01-01	43.06490000000000000
1993-01-01	25.78940000000000000
1994-01-01	7.84261000000000050
1995-01-01	1.50850000000000000
1996-01-01	1.27400000000000000
1997-01-01	1.34197000000000000
1998-01-01	3.88795999999999960
1999-01-01	8.26657000000000000
2000-01-01	11.00470000000000000
2001-01-01	8.01461000000000100
2002-01-01	5.00854000000000000
2003-01-01	6.82274000000000000
2004-01-01	5.97645999999999900
2005-01-01	5.17328000000000000
2006-01-01	4.24468000000000100
2007-01-01	3.13686000000000000
2008-01-01	2.09925999999999970
2009-01-01	3.58756000000000000
2010-01-01	4.38108000000000000
2011-01-01	3.41541999999999970
2012-01-01	2.80262999999999970
2013-01-01	4.41825000000000000
2014-01-01	5.12361000000000000
2015-01-01	8.48075000000000000
2016-01-01	12.03840000000000000