Year	Percent
1973-01-01	27.952600000000000
1974-01-01	28.156999999999996
1975-01-01	31.467200000000000
1976-01-01	35.880900000000000
1977-01-01	36.302500000000000
1978-01-01	37.187700000000000
1979-01-01	35.071999999999996
1980-01-01	40.047600000000000
1981-01-01	48.094300000000000
1982-01-01	50.355500000000000
1983-01-01	49.666500000000000
1984-01-01	54.358000000000004
1985-01-01	56.661800000000000
1986-01-01	65.425800000000000
1987-01-01	54.951300000000000
1988-01-01	54.840600000000000
1989-01-01	50.854900000000000
1990-01-01	48.533200000000000
1991-01-01	54.512600000000000
1992-01-01	56.353200000000000
1993-01-01	62.596600000000000
1994-01-01	61.736800000000000
1995-01-01	62.584900000000000
1996-01-01	64.593700000000000
1997-01-01	68.083800000000000
1998-01-01	69.549700000000000
1999-01-01	71.572900000000000
2000-01-01	70.643500000000000
2001-01-01	73.758500000000000
2002-01-01	78.342500000000000
2003-01-01	78.781200000000000
2004-01-01	78.391900000000000
2005-01-01	77.228400000000000
2006-01-01	71.741100000000000
2007-01-01	64.227500000000000
2008-01-01	66.210200000000000
2009-01-01	65.350100000000000
2010-01-01	61.929400000000000
2011-01-01	61.372900000000000
2012-01-01	61.251400000000000
2013-01-01	63.850900000000000
2014-01-01	64.961400000000000
2015-01-01	69.211500000000000
2016-01-01	84.054200000000000