Year	Percent
1973-01-01	12.63050
1974-01-01	12.14290
1975-01-01	11.59720
1976-01-01	11.16700
1977-01-01	10.10060
1978-01-01	9.80711
1979-01-01	9.44357
1980-01-01	12.15720
1981-01-01	15.15860
1982-01-01	15.81020
1983-01-01	15.48170
1984-01-01	17.93120
1985-01-01	19.04270
1986-01-01	20.88400
1987-01-01	22.96620
1988-01-01	19.01240
1989-01-01	21.75120
1990-01-01	23.22010
1991-01-01	22.15290
1992-01-01	22.16820
1993-01-01	21.48110
1994-01-01	19.92560
1995-01-01	20.16870
1996-01-01	21.06420
1997-01-01	23.32960
1998-01-01	23.51960
1999-01-01	20.30260
2000-01-01	18.69700
2001-01-01	18.79080
2002-01-01	16.46960
2003-01-01	14.91560
2004-01-01	15.82520
2005-01-01	16.91920
2006-01-01	18.85850
2007-01-01	20.32870
2008-01-01	24.12370
2009-01-01	27.30100
2010-01-01	24.17070
2011-01-01	24.52050
2012-01-01	26.34380
2013-01-01	29.46870
2014-01-01	29.89870
2015-01-01	32.58840
2016-01-01	33.32990