Year	Percent
1974-01-01	76.8000000000000000
1975-01-01	78.2009000000000000
1976-01-01	76.0242000000000000
1977-01-01	76.4553000000000000
1978-01-01	71.3128000000000000
1979-01-01	63.6297000000000000
1980-01-01	14.6818000000000000
1981-01-01	36.9827000000000000
1982-01-01	29.5719000000000000
1983-01-01	24.8500000000000000
1984-01-01	26.2410000000000000
1985-01-01	22.9055000000000000
1986-01-01	22.3115000000000000
1987-01-01	19.8204000000000000
1988-01-01	16.1607000000000000
1989-01-01	17.1525000000000000
1990-01-01	17.1525000000000000
1991-01-01	13.1579000000000000
1992-01-01	16.2550000000000000
1993-01-01	14.5294000000000000
1994-01-01	18.2415000000000000
1995-01-01	11.6471000000000000
1996-01-01	3.4128600000000000
1997-01-01	4.4572300000000000
1998-01-01	3.9437300000000004
1999-01-01	3.8408200000000000
2000-01-01	2.9824900000000003
2001-01-01	3.5219600000000000
2002-01-01	3.4489099999999997
2003-01-01	3.4228900000000000
2004-01-01	4.0321099999999990
2005-01-01	4.7470800000000000
2006-01-01	5.7100200000000000
2007-01-01	6.9429300000000005
2008-01-01	9.0680800000000000
2009-01-01	12.3231000000000000
2010-01-01	39.1097000000000000
2011-01-01	44.7076000000000000
2012-01-01	46.7739000000000000
2013-01-01	52.3096000000000000