Year	Percent
1966-01-01	78.2584
1967-01-01	74.8678
1968-01-01	76.4925
1969-01-01	80.1763
1970-01-01	76.9089
1971-01-01	66.3489
1972-01-01	63.2947
1973-01-01	64.1639
1974-01-01	63.1807
1975-01-01	58.5137
1976-01-01	53.0506
1977-01-01	52.5061
1978-01-01	49.7358
1979-01-01	44.7015
1980-01-01	40.8068
1981-01-01	44.3729
1982-01-01	45.2380
1983-01-01	21.6619
1984-01-01	12.6772
1985-01-01	12.6889
1986-01-01	21.3958
1987-01-01	21.3958
1988-01-01	21.3958
1989-01-01	21.3958
1990-01-01	21.3958
1991-01-01	21.3958
1992-01-01	14.4884
1993-01-01	17.6673
1994-01-01	21.3558
1995-01-01	22.2693
1996-01-01	24.6833
1997-01-01	27.9758
1998-01-01	29.5789
1999-01-01	30.7956
2000-01-01	33.3229
2001-01-01	42.0323
2002-01-01	51.0414
2003-01-01	54.1987
2004-01-01	56.0941
2005-01-01	57.2039
2006-01-01	61.3783
2007-01-01	62.3692
2008-01-01	62.8179
2009-01-01	65.4946
2010-01-01	65.7581
2011-01-01	62.8047
2012-01-01	60.8517
2013-01-01	59.9949
2014-01-01	70.4919
2015-01-01	86.2294
2016-01-01	87.1787