Year	Percent
1973-01-01	15.2294
1974-01-01	15.2303
1975-01-01	17.2915
1976-01-01	17.8333
1977-01-01	18.2153
1978-01-01	20.0328
1979-01-01	20.6821
1980-01-01	19.6315
1981-01-01	21.4891
1982-01-01	21.4983
1983-01-01	23.5634
1984-01-01	24.7959
1985-01-01	24.2563
1986-01-01	18.1651
1987-01-01	14.6663
1988-01-01	14.0401
1989-01-01	14.2916
1990-01-01	19.6370
1991-01-01	25.3000
1992-01-01	30.4319
1993-01-01	35.0719
1994-01-01	35.1554
1995-01-01	38.7234
1996-01-01	36.5860
1997-01-01	46.7312
1998-01-01	54.5423
1999-01-01	56.6874
2000-01-01	60.6179
2001-01-01	61.0578
2002-01-01	63.4129
2003-01-01	61.8965
2004-01-01	61.3564
2005-01-01	62.9903
2006-01-01	65.5429
2007-01-01	72.0237
2008-01-01	79.3203
2009-01-01	87.5848
2010-01-01	86.4605
2011-01-01	84.6841
2012-01-01	89.5399
2013-01-01	90.3022
2014-01-01	89.9495
2015-01-01	85.9328
2016-01-01	85.3804