Year	Percent
1971-01-01	0.10285899999999999
1972-01-01	0.83532000000000010
1973-01-01	1.16711000000000000
1974-01-01	1.35196000000000000
1975-01-01	4.33726999999999900
1976-01-01	7.90433999999999950
1977-01-01	14.07920000000000000
1978-01-01	19.96210000000000000
1979-01-01	21.18300000000000300
1980-01-01	16.60480000000000000
1981-01-01	15.40330000000000000
1982-01-01	13.84900000000000000
1983-01-01	11.91030000000000000
1984-01-01	11.29110000000000000
1985-01-01	12.46010000000000000
1986-01-01	16.18440000000000000
1987-01-01	19.90130000000000000
1988-01-01	20.72420000000000000
1989-01-01	20.38410000000000000
1990-01-01	16.59380000000000000
1991-01-01	16.16120000000000000
1992-01-01	15.12250000000000000
1993-01-01	15.91240000000000000
1994-01-01	14.85780000000000000
1995-01-01	12.07940000000000000
1996-01-01	11.36020000000000000
1997-01-01	13.18280000000000000
1998-01-01	18.02610000000000000
1999-01-01	18.71390000000000000
2000-01-01	21.83750000000000000
2001-01-01	22.20070000000000000
2002-01-01	23.83450000000000000
2003-01-01	26.77170000000000000
2004-01-01	28.35140000000000000
2005-01-01	25.12260000000000000
2006-01-01	31.70040000000000000
2007-01-01	35.84150000000000000
2008-01-01	35.65140000000000000
2009-01-01	47.01280000000000000
2010-01-01	46.48980000000000000
2011-01-01	46.81740000000000000
2012-01-01	52.01699999999999600
2013-01-01	54.11960000000000000
2014-01-01	51.75670000000000000
2015-01-01	60.80950000000000000
2016-01-01	59.95410000000000000