Year	Percent
1970-01-01	2.164300000000000
1971-01-01	2.003150000000000
1972-01-01	2.197290000000000
1973-01-01	2.425830000000000
1974-01-01	2.646370000000000
1975-01-01	3.837950000000000
1976-01-01	5.297870000000000
1977-01-01	6.939800000000000
1978-01-01	9.673930000000000
1979-01-01	8.096330000000000
1980-01-01	5.867150000000000
1981-01-01	6.158790000000000
1982-01-01	8.811330000000000
1983-01-01	11.095200000000000
1984-01-01	11.542000000000000
1985-01-01	12.396500000000000
1986-01-01	14.407900000000000
1987-01-01	15.397400000000000
1988-01-01	16.503000000000000
1989-01-01	16.042700000000000
1990-01-01	13.028500000000000
1991-01-01	13.449100000000000
1992-01-01	15.023600000000000
1993-01-01	16.038000000000000
1994-01-01	15.777999999999999
1995-01-01	15.459500000000000
1996-01-01	14.516700000000000
1997-01-01	14.961600000000000
1998-01-01	17.433000000000000
1999-01-01	16.220800000000000
2000-01-01	15.187700000000000
2001-01-01	17.712000000000000
2002-01-01	19.725700000000000
2003-01-01	19.627100000000000
2004-01-01	19.128500000000000
2005-01-01	17.155000000000000
2006-01-01	16.383100000000000
2007-01-01	17.632200000000000
2008-01-01	16.993400000000000
2009-01-01	24.029200000000000
2010-01-01	24.409200000000000
2011-01-01	23.481700000000000
2012-01-01	25.207600000000000
2013-01-01	28.776100000000000
2014-01-01	32.576900000000000
2015-01-01	40.061900000000000
2016-01-01	40.846900000000000