Year	Percent
1974-01-01	12.9753
1975-01-01	10.5681
1976-01-01	10.7124
1977-01-01	11.1513
1978-01-01	11.1770
1979-01-01	11.9253
1980-01-01	10.4081
1981-01-01	10.8925
1982-01-01	11.0533
1983-01-01	12.0376
1984-01-01	14.1834
1985-01-01	15.3904
1986-01-01	15.3904
1987-01-01	15.3904
1988-01-01	15.3904
1989-01-01	15.3904
1990-01-01	15.3904
1991-01-01	15.3904
1992-01-01	15.3904
1993-01-01	21.4204
1994-01-01	21.4182
1995-01-01	22.6598
1996-01-01	22.7958
1997-01-01	23.4128
1998-01-01	23.3028
1999-01-01	23.9550
2000-01-01	26.2263
2001-01-01	32.3876
2002-01-01	37.7997
2003-01-01	39.0540
2004-01-01	40.5257
2005-01-01	42.0457
2006-01-01	44.0024
2007-01-01	45.0954
2008-01-01	45.9340
2009-01-01	47.0693
2010-01-01	48.9839
2011-01-01	51.6068
2012-01-01	52.2177
2013-01-01	53.7939
2014-01-01	55.2812
2015-01-01	56.1271
2016-01-01	57.1849