Year	Percent
1975-01-01	3.171670000000000
1976-01-01	3.248390000000000
1977-01-01	3.061150000000000
1978-01-01	15.312100000000000
1979-01-01	14.530100000000000
1980-01-01	2.529210000000000
1981-01-01	2.260010000000000
1982-01-01	2.118020000000000
1983-01-01	2.055670000000000
1984-01-01	2.128380000000000
1985-01-01	4.347270000000000
1986-01-01	6.532719999999999
1987-01-01	6.461220000000000
1988-01-01	6.843620000000000
1989-01-01	12.649000000000001
1990-01-01	16.537700000000000
1991-01-01	14.486200000000000
1992-01-01	11.847400000000000
1993-01-01	11.882200000000000
1994-01-01	13.765300000000000
1995-01-01	13.254900000000000
1996-01-01	12.959800000000000
1997-01-01	15.172800000000000
1998-01-01	8.946260000000000
1999-01-01	8.099210000000001
2000-01-01	14.857000000000001
2001-01-01	13.811700000000000
2002-01-01	14.100300000000000
2003-01-01	18.488200000000000
2004-01-01	24.875000000000000
2005-01-01	33.918800000000000
2006-01-01	47.663100000000000
2007-01-01	57.318100000000000
2008-01-01	38.615000000000000
2009-01-01	23.241000000000000
2010-01-01	29.940600000000000
2011-01-01	25.461400000000000
2012-01-01	22.548800000000000
2013-01-01	26.350300000000000
2014-01-01	24.252400000000000
2015-01-01	23.110300000000000
2016-01-01	27.580900000000000
2017-01-01	32.777500000000000