Year	Percent
1980-01-01	1.8266900000000001
1981-01-01	1.7287500000000000
1982-01-01	2.0143900000000000
1983-01-01	2.0764600000000000
1984-01-01	1.9081299999999999
1985-01-01	1.8860500000000000
1986-01-01	2.4755100000000000
1987-01-01	3.1571599999999997
1988-01-01	6.2186200000000000
1989-01-01	7.7690399999999995
1990-01-01	7.0396199999999990
1991-01-01	7.3855900000000000
1992-01-01	5.5845600000000000
1993-01-01	5.7577500000000000
1994-01-01	5.6234699999999990
1995-01-01	5.0720600000000000
1996-01-01	4.0128400000000000
1997-01-01	3.9693000000000000
1998-01-01	3.9256599999999997
1999-01-01	3.6981000000000000
2000-01-01	3.8979900000000000
2001-01-01	3.9732100000000000
2002-01-01	3.6040500000000000
2003-01-01	3.3845099999999997
2004-01-01	3.0766299999999998
2005-01-01	2.8488200000000000
2006-01-01	2.6490600000000000
2007-01-01	2.4731700000000000
2008-01-01	2.4291900000000000
2009-01-01	2.3754700000000000
2010-01-01	2.1930500000000000
2011-01-01	2.3284500000000000
2012-01-01	3.1562700000000000
2013-01-01	3.7492300000000003
2014-01-01	3.4685400000000000
2015-01-01	3.8563800000000000
2016-01-01	4.9651400000000000